Adding mattermost-govet to the pipeline (#13257)

* Adding mattermost-govet to the pipeline

* Trying to fix circleCI config

* Trying to fix circleCI config

* Trying to fix circleCI config

* Trying to fix circleCI config

* Update Makefile

Co-Authored-By: Ben Schumacher <ben.schumacher@mattermost.com>

* Update Makefile

Co-Authored-By: Ben Schumacher <ben.schumacher@mattermost.com>

* Addressing PR review comments

* Addressing PR review comments

* Addressing PR review comments

* Addressing PR review comments

* Addressing PR review comments

* Addressing PR review comments

* Adding legacy check-licenses task to legacy.mk

* Removing unnecesary GO111MODULE=off lines

* Adding jenkins mattermost-govet installation

build/legacy.mk

@@ -4,6 +4,9 @@ test-te: test-server
 # test-ee used to just run the enterprise edition tests, but now runs whatever is available
 test-ee: test-server
 
+# check-licenses was used to check the license of the files, but now is done through mattermost-govet
+check-licenses: vet
+
 # clean old docker images
 clean-old-docker:
 	@echo Removing docker containers