Pin Maven to 3.8.8 for Java 11 compatibility (#104)

* Pin GitHub Actions runners to ubuntu-22.04

The ubuntu-latest runner switched from Ubuntu 22.04 to Ubuntu 24.04
on Jan 17, 2025, which includes Maven 3.9.12. Maven 3.9.6+ enforces
stricter Java prerequisites for plugins.

While quarkus-maven-plugin 3.6.9 requires Java 17 to execute, our
codebase uses Datastax Cassandra Driver 3.7.2 (from path-mapped-storage)
which only supports Java 8-11. Upgrading to Datastax Driver 4.x would
be a major migration.

Pinning to ubuntu-22.04 keeps us on an older Maven version that doesn't
enforce the plugin Java requirement as strictly, allowing builds to
continue on Java 11.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* Install Maven 3.8.8 explicitly to avoid Java 17 requirement

Maven 3.9.0+ enforces stricter Java prerequisites for plugins.
The quarkus-maven-plugin:3.6.9 requires Java 17 to execute when
used with Maven 3.9.x, even though it's compiled for Java 11.

Maven 3.8.8 (last pre-3.9 version) doesn't enforce this check,
allowing the build to work with Java 11.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: ruhan1

.github/workflows/merge-build.yml

@@ -25,7 +25,7 @@ jobs:
   publish-snapshot:
     name: publish to oss sonatype & push image
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     permissions: 
       contents: read
@@ -44,6 +44,11 @@ jobs:
         architecture: x64
         java-version: 11
 
+    - name: Set up Maven
+      uses: stCarolas/setup-maven@v4.5
+      with:
+        maven-version: 3.8.8
+
     - name: maven-settings-xml-action
       uses: whelk-io/maven-settings-xml-action@v14
       if: ${{ github.event.repository.fork == false }}

.github/workflows/pr-build.yml

@@ -24,7 +24,7 @@ on: [pull_request]
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     steps:
     - uses: actions/checkout@v2
@@ -35,6 +35,11 @@ jobs:
         java-version: '11'
         distribution: 'adopt'
 
+    - name: Set up Maven
+      uses: stCarolas/setup-maven@v4.5
+      with:
+        maven-version: 3.8.8
+
     - name: maven-settings-xml-action
       uses: whelk-io/maven-settings-xml-action@v14
       with: