Introduce actionlint to lint GitHub Actions workflows (crystal-lang#15449)

Author: straight-shoota

.github/actionlint.yaml

@@ -0,0 +1,23 @@
+self-hosted-runner:
+  # Labels of self-hosted runner in array of strings.
+  labels:
+    - runs-on
+    - runner=*
+    - family=*
+    - ram=*
+
+# Configuration variables in array of strings defined in your repository or
+# organization. `null` means disabling configuration variables check.
+# Empty array means no configuration variable is allowed.
+config-variables: null
+
+# Configuration for file paths. The keys are glob patterns to match to file
+# paths relative to the repository root. The values are the configurations for
+# the file paths. Note that the path separator is always '/'.
+# The following configurations are available.
+#
+# "ignore" is an array of regular expression patterns. Matched error messages
+# are ignored. This is similar to the "-ignore" command line option.
+paths:
+#  .github/workflows/**/*.yml:
+#    ignore: []

.github/workflows/docs.yml

@@ -31,7 +31,7 @@ jobs:
         run: bin/ci with_build_env 'make crystal docs threads=1'
 
       - name: Set revision
-        run: echo $GITHUB_SHA > ./docs/revision.txt
+        run: echo "$GITHUB_SHA" > ./docs/revision.txt
 
       - name: Configure AWS Credentials
         uses: aws-actions/configure-aws-credentials@v4

.github/workflows/lint-actionlint.yml

@@ -0,0 +1,16 @@
+name: Lint GitHub Actions workflows
+on:
+  push:
+    paths:
+      - '.github/workflows/*.yml'
+  pull_request:
+    paths:
+      - '.github/workflows/*.yml'
+
+jobs:
+  actionlint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Check workflow files
+        uses: docker://rhysd/actionlint:latest

.github/workflows/wasm32.yml

@@ -32,7 +32,7 @@ jobs:
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           apt-add-repository -y deb http://apt.llvm.org/noble/ llvm-toolchain-noble-18 main
           apt-get install -y llvm-18-dev lld-18
-          ln -s $(which wasm-ld-18) /usr/bin/wasm-ld
+          ln -s "$(which wasm-ld-18)" /usr/bin/wasm-ld
 
       - name: Download wasm32 libs
         run: |