Fix maven at 3.8.7

Until we update Tycho to 3.0.3+ we use the older Maven

Thanks to @ghentschke for figuring this out in
eclipse-cdt/cdt-lsp@f776179

Fixes #308

.github/workflows/build-test.yml

@@ -31,6 +31,10 @@ jobs:
         java-version: '17'
         distribution: 'temurin'
         cache: maven
+    - name: Setup Maven
+      uses: stCarolas/setup-maven@v.4.5
+      with:
+        maven-version: 3.8.7
     - name: Install GCC & GDB & other build essentials
       run: |
         sudo apt-get -y install build-essential gcc g++ gdb gdbserver

.github/workflows/code-cleanliness.yml

@@ -21,6 +21,10 @@ jobs:
         java-version: '17'
         distribution: 'temurin'
         cache: maven
+    - name: Setup Maven
+      uses: stCarolas/setup-maven@v.4.5
+      with:
+        maven-version: 3.8.7
     - name: Install dependencies
       run: |
         sudo apt-get update && sudo apt-get install -y --no-install-recommends \