fix(purpur): apply log4j mitigations specific to Purpur (#1280)

.github/workflows/build-multiarch.yml

@@ -8,6 +8,7 @@ on:
       - java11*
       - java16*
       - java17*
+      - test/**
     tags:
       - "[0-9]+.[0-9]+.[0-9]+"
       - "[0-9]+.[0-9]+.[0-9]+-java8-multiarch"
@@ -56,7 +57,7 @@ jobs:
 
       - name: Build for test
         uses: docker/build-push-action@v2.7.0
-        if: github.ref_name == 'master'
+        if: github.ref_name == 'master' || startsWith(github.ref_name, 'test/')
         with:
           context: .
           platforms: linux/amd64
@@ -70,7 +71,7 @@ jobs:
 
       - name: Run tests
         # It is assumed that image variants are merged from master and tested there
-        if: github.ref_name == 'master'
+        if: github.ref_name == 'master' || startsWith(github.ref_name, 'test/')
         run: |
           tests/test.sh
 
@@ -80,7 +81,7 @@ jobs:
         with:
           context: .
           platforms: linux/amd64,linux/arm/v7,linux/arm64
-          push: ${{ github.event_name != 'pull_request' }}
+          push: true
           tags: ${{ steps.meta.outputs.tags }}
           # ensure latest base image is used
           pull: true