doc: update the release process to remove Travis CI

Remove the Travis CI option for the Coverity checks.  We can investigate
add Coverity to the GitHub Actions in the future, but right now just
stick to manual submissions.

Signed-off-by: Paul Moore <[email protected]>

Author: pcmoore

doc/admin/RELEASE_PROCESS.md

@@ -29,11 +29,6 @@ release.
 	# make coverity-tarball
 	<submit tarball manually>
 
-	... or ...
-
-	# git push -f coverity-scan
-	<leverage existing Travis CI infrastructure>
-
 #### 6. Perform any distribution test builds
 
   * Fedora Rawhide