build: publish the aar to the github packages maven registry

Adds maven-publish (dev.firechip:cobs_codec_kt) and a publish workflow.

Author: ajsb85

.github/workflows/publish-maven.yml

@@ -0,0 +1,33 @@
+name: Publish to GitHub Packages
+
+on:
+  push:
+    tags:
+      - "v*"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  publish:
+    name: Publish Maven package
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/setup-java@v5
+        with:
+          distribution: temurin
+          java-version: "17"
+      - uses: android-actions/setup-android@v4
+      - name: Install SDK packages
+        run: sdkmanager "platforms;android-35" "build-tools;36.0.0"
+      - name: Test and publish to GitHub Packages
+        env:
+          GITHUB_ACTOR: ${{ github.actor }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: >-
+          ./gradlew :cobs:testDebugUnitTest
+          :cobs:publishReleasePublicationToGitHubPackagesRepository
+          --console=plain

README.md

@@ -26,9 +26,40 @@ as a serial/UART, USB, or BLE link.
 
 ## Install
 
-The `.aar` is attached to each
-[GitHub release](https://github.com/firechip/cobs_codec_kt/releases). Download
-`cobs_codec_kt-<version>.aar` into your app's `libs/` directory and add:
+### Gradle (GitHub Packages)
+
+The library is published to the GitHub Packages Maven registry as
+`dev.firechip:cobs_codec_kt`. Add the repository and the dependency:
+
+```kotlin
+repositories {
+    maven {
+        url = uri("https://maven.pkg.github.com/firechip/cobs_codec_kt")
+        credentials {
+            username = providers.gradleProperty("gpr.user").orNull
+                ?: System.getenv("GITHUB_ACTOR")
+            password = providers.gradleProperty("gpr.key").orNull
+                ?: System.getenv("GITHUB_TOKEN")
+        }
+    }
+}
+
+dependencies {
+    implementation("dev.firechip:cobs_codec_kt:1.0.0")
+}
+```
+
+> GitHub Packages requires authentication even for public packages. Use a GitHub
+> [personal access token](https://github.com/settings/tokens) with the
+> `read:packages` scope, set as `gpr.user` / `gpr.key` in
+> `~/.gradle/gradle.properties` (or the `GITHUB_ACTOR` / `GITHUB_TOKEN`
+> environment variables).
+
+### Direct `.aar` download
+
+Alternatively, the `.aar` is attached to every
+[GitHub release](https://github.com/firechip/cobs_codec_kt/releases) and needs no
+authentication:
 
 ```kotlin
 dependencies {

cobs/build.gradle.kts

@@ -2,8 +2,12 @@ import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 plugins {
     id("com.android.library")
+    id("maven-publish")
 }
 
+group = "dev.firechip"
+version = "1.0.0"
+
 android {
     namespace = "dev.firechip.cobs"
     compileSdk = 35
@@ -28,6 +32,12 @@ android {
             it.useJUnit()
         }
     }
+
+    publishing {
+        singleVariant("release") {
+            withSourcesJar()
+        }
+    }
 }
 
 kotlin {
@@ -39,3 +49,56 @@ kotlin {
 dependencies {
     testImplementation("junit:junit:4.13.2")
 }
+
+publishing {
+    publications {
+        register<MavenPublication>("release") {
+            afterEvaluate {
+                from(components["release"])
+            }
+            groupId = "dev.firechip"
+            artifactId = "cobs_codec_kt"
+            version = project.version.toString()
+            pom {
+                name = "cobs_codec_kt"
+                description =
+                    "Pure-Kotlin Consistent Overhead Byte Stuffing (COBS) and " +
+                    "COBS/R for Android."
+                url = "https://github.com/firechip/cobs_codec_kt"
+                licenses {
+                    license {
+                        name = "MIT"
+                        url =
+                            "https://github.com/firechip/cobs_codec_kt/blob/main/LICENSE"
+                    }
+                }
+                developers {
+                    developer {
+                        id = "ajsb85"
+                        name = "Alexander Salas Bastidas"
+                        email = "ajsb85@firechip.dev"
+                    }
+                }
+                scm {
+                    url = "https://github.com/firechip/cobs_codec_kt"
+                    connection =
+                        "scm:git:https://github.com/firechip/cobs_codec_kt.git"
+                    developerConnection =
+                        "scm:git:ssh://git@github.com/firechip/cobs_codec_kt.git"
+                }
+            }
+        }
+    }
+    repositories {
+        maven {
+            name = "GitHubPackages"
+            url = uri("https://maven.pkg.github.com/firechip/cobs_codec_kt")
+            credentials {
+                username = System.getenv("GITHUB_ACTOR")
+                    ?: providers.gradleProperty("gpr.user").orNull
+                password = System.getenv("GITHUB_TOKEN")
+                    ?: providers.gradleProperty("gpr.key").orNull
+            }
+        }
+    }
+}