Fix Typos

Fix Typos

.gitlab/issue_templates/Release Checklist.md:242:31: "begining" is a misspelling of "beginning"
.gitlab/issue_templates/Release Checklist.md:287:35: "begining" is a misspelling of "beginning"
ci/release_packagecloud:16:14: "Unkown" is a misspelling of "Unknown"
docs/configuration/proxy.md:190:48: "initally" is a misspelling of "initially"
docs/executors/kubernetes.md:132:0: "usefull" is a misspelling of "useful"
executors/kubernetes/util_test.go:77:40: "precendece" is a misspelling of "precedence"
executors/shell/executor_shell_test.go:745:34: "commited" is a misspelling of "committed"