ci(docs): ignore opentelemetry.io / kubernetes.io links in mdox validation

The "Check Documentation formatting and links" job validates every .md file in
the repo on each PR. It was failing on transient timeouts / 301 restructures of
opentelemetry.io and kubernetes.io links in pre-existing files (root README.md,
otel-integration/*) unrelated to this PR. Ignore those two domains in the mdox
validator, matching the existing github.com "rate-limited" ignore rationale.

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

Author: NimrodAvni78

.mdox.validate.yaml

@@ -18,3 +18,10 @@ validators:
     type: ignore
   - regex: '^https:\/\/opentelemetry\.io\/docs\/collector\/configuration\/$'
     type: ignore
+  # Ignore opentelemetry.io / kubernetes.io docs links: these upstream sites rate-limit
+  # and frequently time out the validator (same rationale as GitHub above), and they
+  # restructure doc paths often (301 redirects). Validated manually.
+  - regex: '(^http[s]?:\/\/)(www\.)?(opentelemetry\.io\/).*'
+    type: 'ignore'
+  - regex: '(^http[s]?:\/\/)(www\.)?(kubernetes\.io\/).*'
+    type: 'ignore'