exclude .git from copyright linter (#33359)

When doing the copyright linting we collect all files matching *.go. If a branch is named with a name ending with .go, like NDMII-3313-integration-metric-stats.go you end up with a file .git/logs/refs/remotes/origin/NDMII-3313-integration-metric-stats.go that we are trying to lint. This PR exclude the .git folder from the linter.

(cherry picked from commit 7b0a606)

tasks/libs/types/copyright.py

@@ -24,6 +24,8 @@
 
 # These path patterns are excluded from checks
 PATH_EXCLUSION_REGEX = [
+    # Git internal folder
+    '/.git/',
     # These are auto-generated files but without headers to indicate it
     '/vendor/',
     '/pkg/clusteragent/autoscaling/custommetrics/api/generated/',