fix: update bash script, pipe xargs

Changes:

- applied Sergio's suggestion from: https://github.com/asyncapi/spec/pull/1046/files#r1555684920
- added comment as to why we're skipping the mentioned directory

.github/workflows/validate-examples.yml

@@ -24,4 +24,5 @@ jobs:
         run: npm install -g @asyncapi/cli
       - name: Validate AsyncAPI documents
         run: |
-          find examples/ \( -path 'examples/social-media/*' -prune \) -o -type f \( -name "*.yml" -o -name "*.yaml" \) -exec asyncapi validate {} \;
+# NOTE: we've excluded the files inside `examples/social-media/common` folder because it contains partial documents which don't comply with the asyncapi document format, hence these files give error during the validation.
+          find examples -type f \( -name "*.yml" -o -name "*.yaml" \) -not -path 'examples/social-media/common/*' | xargs -P 10 -L 1 asyncapi validate