Try installing unzip package in runner

.gitlab-ci.yml

@@ -24,6 +24,7 @@ pmd:
   before_script:
     - 'export VERSION="6.40.0"'
     - 'wget "https://github.com/pmd/pmd/releases/download/pmd_releases%2F$VERSION/pmd-bin-$VERSION.zip"'
+    - 'apt-get install unzip'
     - 'unzip "pmd-bin-$VERSION.zip"'
   script:
     - '"pmd-bin-$VERSION/bin/run.sh" pmd -d src/main/java -f textcolor -R pmd_rules.xml 2>&1 | tee pmd.log'