Fixed shellcheck error with static checks (apache#15450)

Shellcheck released today broke static checks. This PR fixes it
and pins shellcheck to specific version to avoid it in the future.

Author: potiuk

.pre-commit-config.yaml

@@ -428,7 +428,7 @@ repos:
       - id: shellcheck
         name: Check Shell scripts syntax correctness
         language: docker_image
-        entry: koalaman/shellcheck:stable -x -a
+        entry: koalaman/shellcheck:v0.7.2 -x -a
         files: ^breeze$|^breeze-complete$|\.sh$|^hooks/build$|^hooks/push$|\.bash$|\.bats$
       - id: bats-tests
         name: Run BATS bash tests for changed Breeze bash files

dev/remove_artifacts.sh

@@ -40,7 +40,6 @@ if [[ -z ${GITHUB_TOKEN} ]]; then
     echo 2>&1
     exit 2
 fi
-GITHUB_TOKEN=${GITHUB_TOKEN}
 readonly GITHUB_TOKEN
 
 function github_api_call() {