ci: Make `find` for test reports more specific

Don't use all `*.json` files blindly, take only these that are likely to
be reports from go test.
Also, use `find ... -exec` instead of piping results to `xargs`.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

.github/workflows/.test.yml

@@ -97,7 +97,7 @@ jobs:
       -
         name: Create summary
         run: |
-          teststat -markdown $(find /tmp/reports -type f -name '*.json' -print0 | xargs -0) >> $GITHUB_STEP_SUMMARY
+          find /tmp/reports -type f -name '*-go-test-report.json' -exec teststat -markdown {} \+ >> $GITHUB_STEP_SUMMARY
 
   docker-py:
     runs-on: ubuntu-20.04
@@ -299,7 +299,7 @@ jobs:
       -
         name: Create summary
         run: |
-          teststat -markdown $(find /tmp/reports -type f -name '*.json' -print0 | xargs -0) >> $GITHUB_STEP_SUMMARY
+          find /tmp/reports -type f -name '*-go-test-report.json' -exec teststat -markdown {} \+ >> $GITHUB_STEP_SUMMARY
 
   integration-cli-prepare:
     runs-on: ubuntu-20.04
@@ -438,4 +438,4 @@ jobs:
       -
         name: Create summary
         run: |
-          teststat -markdown $(find /tmp/reports -type f -name '*.json' -print0 | xargs -0) >> $GITHUB_STEP_SUMMARY
+          find /tmp/reports -type f -name '*-go-test-report.json' -exec teststat -markdown {} \+ >> $GITHUB_STEP_SUMMARY

.github/workflows/.windows.yml

@@ -215,7 +215,7 @@ jobs:
       -
         name: Create summary
         run: |
-          teststat -markdown $(find /tmp/artifacts -type f -name '*.json' -print0 | xargs -0) >> $GITHUB_STEP_SUMMARY
+          find /tmp/artifacts -type f -name '*-go-test-report.json' -exec teststat -markdown {} \+ >> $GITHUB_STEP_SUMMARY
 
   integration-test-prepare:
     runs-on: ubuntu-latest
@@ -546,4 +546,4 @@ jobs:
       -
         name: Create summary
         run: |
-          teststat -markdown $(find /tmp/reports -type f -name '*.json' -print0 | xargs -0) >> $GITHUB_STEP_SUMMARY
+          find /tmp/reports -type f -name '*-go-test-report.json' -exec teststat -markdown {} \+ >> $GITHUB_STEP_SUMMARY