Increased minimum Maven version to 3.8.8. (#648)

No need to support JRE 1.6 since Kotlin doesn't anymore.

.github/workflows/maven-build.yml

@@ -39,8 +39,8 @@ jobs:
     strategy:
       matrix:
         maven-version:
-          - '3.5.4'
-          - '3.9.4'
+          - '3.8.8'
+          - '3.9.9'
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -76,5 +76,5 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Code coverage report
-        if: matrix.maven-version == '3.9.4'
+        if: matrix.maven-version == '3.9.9'
         uses: codecov/codecov-action@v5.0.2

.mvn/wrapper/maven-wrapper.properties

@@ -14,5 +14,6 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.4/apache-maven-3.9.4-bin.zip
-wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.2.0/maven-wrapper-3.2.0.jar
+wrapperVersion=3.3.2
+distributionType=only-script
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.9/apache-maven-3.9.9-bin.zip