ci: harden Remove Snapshots step against silent failure

From a Gemini CI review: `find ... | xargs rm -rf` masks a find failure
(xargs exits 0 on empty stdin), and GNU xargs also runs `rm` once with no
operands on empty input. Add `set -o pipefail` so a find failure fails the
step, and `xargs -r` so rm is skipped when there is nothing to remove.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: robertlazarski

.github/workflows/ci.yml

@@ -56,7 +56,9 @@ jobs:
     - name: Build
       run: mvn -B -e -Papache-release -Dgpg.skip=true -Dmaven.compiler.release=${{ matrix.java }} verify
     - name: Remove Snapshots
-      run: find ~/.m2/repository -name '*-SNAPSHOT' -a -type d -print0 | xargs -0 rm -rf
+      run: |
+        set -o pipefail
+        find ~/.m2/repository -name '*-SNAPSHOT' -a -type d -print0 | xargs -0 -r rm -rf
   site:
     name: Site
     runs-on: ubuntu-24.04
@@ -79,7 +81,9 @@ jobs:
     - name: Build
       run: mvn -B -e -Dmaven.test.skip=true -Dmaven.compiler.release=${{ env.BASE_JAVA_VERSION }} package site-deploy
     - name: Remove Snapshots
-      run: find ~/.m2/repository -name '*-SNAPSHOT' -a -type d -print0 | xargs -0 rm -rf
+      run: |
+        set -o pipefail
+        find ~/.m2/repository -name '*-SNAPSHOT' -a -type d -print0 | xargs -0 -r rm -rf
   deploy:
     if: github.event_name == 'push' && github.ref == 'refs/heads/master' && github.repository == 'apache/axis-axis2-java-core'
     name: Deploy
@@ -112,4 +116,6 @@ jobs:
         NEXUS_USER: ${{ secrets.NEXUS_USER }}
         NEXUS_PW: ${{ secrets.NEXUS_PW }}
     - name: Remove Snapshots
-      run: find ~/.m2/repository -name '*-SNAPSHOT' -a -type d -print0 | xargs -0 rm -rf
+      run: |
+        set -o pipefail
+        find ~/.m2/repository -name '*-SNAPSHOT' -a -type d -print0 | xargs -0 -r rm -rf