feat(build): add Ubuntu 26.04 to the Linux package build matrix

Add a build containerfile for ubuntu:26.04, wire it into
create-package.sh, the x86_64 and aarch64 GitHub workflows, and
BUILD.md. Also add an "OS - Ubuntu 26 Basic Service Set" template
to the Icinga Director basket, cloned from the Ubuntu 24 template
with fresh UUIDs so it can be imported side-by-side.

Author: markuslf

.github/workflows/lf-build-linux-aarch64.yml

@@ -4,9 +4,9 @@ on:
   workflow_dispatch:
     inputs:
       target-distros:
-        description: 'Space-separated list of operating systems to compile on and build packages for. Supported: `debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404`. Cannot be empty.'
+        description: 'Space-separated list of operating systems to compile on and build packages for. Supported: `debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404 ubuntu2604`. Cannot be empty.'
         required: true
-        default: 'debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404'
+        default: 'debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404 ubuntu2604'
       version:
         description: 'Package Version'
         required: true

.github/workflows/lf-build-linux-x86_64.yml

@@ -4,9 +4,9 @@ on:
   workflow_dispatch:
     inputs:
       target-distros:
-        description: 'Space-separated list of operating systems to compile on and build packages for. Supported: `debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404`. Cannot be empty.'
+        description: 'Space-separated list of operating systems to compile on and build packages for. Supported: `debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404 ubuntu2604`. Cannot be empty.'
         required: true
-        default: 'debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404'
+        default: 'debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404 ubuntu2604'
       version:
         description: 'Package Version'
         required: true

BUILD.md

@@ -54,7 +54,7 @@ cat > env-file << 'EOF'
 export LFMP_ARCH=x86_64                                   # or "aarch64" if running on ARM64
 export LFMP_VERSION=1.4.0
 export LFMP_PACKAGE_ITERATION=7
-export LFMP_TARGET_DISTROS="debian13 rocky10"              # "debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404"
+export LFMP_TARGET_DISTROS="debian13 rocky10"              # "debian11 debian12 debian13 rocky8 rocky9 rocky10 sle15 sle16 ubuntu2004 ubuntu2204 ubuntu2404 ubuntu2604"
 
 # ---
 # Constants
@@ -145,6 +145,7 @@ SLE 16        ! registry.suse.com/bci/bci-base:16.0
 Ubuntu 20.04  ! docker.io/library/ubuntu:20.04
 Ubuntu 22.04  ! docker.io/library/ubuntu:22.04
 Ubuntu 24.04  ! docker.io/library/ubuntu:24.04
+Ubuntu 26.04  ! docker.io/library/ubuntu:26.04
 ```
 
 > [!NOTE]

CHANGELOG.md

@@ -26,6 +26,7 @@ Build, CI/CD:
 * Add MkDocs-based documentation site, served at <https://linuxfabrik.github.io/monitoring-plugins/> and kept in sync with the repo automatically on every merge to `main`
 * Add support for SLE 15 packages
 * Add support for SLE 16 packages
+* Add support for Ubuntu 26.04 packages, including an "OS - Ubuntu 26 Basic Service Set" template in the Icinga Director basket
 
 
 Monitoring Plugins: