Remove docker credentials prior to tests/s2i

s2i misbehaves if registry credentials are present: tries and fails to query
image metadata from docker.io before each build, etc. See:
openshift/source-to-image#1134

Signed-off-by: Jonathan Dowland <jdowland@redhat.com>

.github/workflows/image-workflow-template.yml

@@ -33,6 +33,12 @@ jobs:
           github_pat: ${{ github.token }}
           s2i: "1.3.4"
 
+      # s2i misbehaves if registry credentials are present: tries and fails to query
+      # image metadata from docker.io before each build, etc. See:
+      # https://github.com/openshift/source-to-image/issues/1134
+      - name: clear docker credentials
+        run: docker logout
+
       - name: Behave Tests
         run: |
           echo /home/runner/work/_temp/openshift-bin >> $GITHUB_PATH