Update github bazelrc (pixie-io#1166)

Summary: Set role to not `CI` since releaase or scan builds shouldn't
affect the test matrix. Also set visiblity to `PUBLIC`.

Relevant Issues: N/A

Type of change: /kind cleanup

Test Plan: Check Buildbuddy for release scans and trivy runs after this
lands.

Signed-off-by: Vihang Mehta <vihang@pixielabs.ai>

ci/github/bazelrc

@@ -8,6 +8,8 @@ common --keep_going
 build --build_metadata=HOST=github-actions
 build --build_metadata=USER=github-actions
 build --build_metadata=REPO_URL=https://github.com/pixie-io/pixie
+build --build_metadata=ROLE=DEV
+build --build_metadata=VISIBILITY=PUBLIC
 build --verbose_failures
 
 test --verbose_failures