The regular expression used to exclude non-shell files is too greedy,
resulting in some shell scripts being excluded from the check:
- hack/validate/vendor and hack/vendor.sh (matched "vendor");
- hack/make/.go-autogen (matched ".go").
Use git pathspec instead, excluding the vendor directory and Python
files only. Drop .go, .bats, and Jenkinsfile exclusions, as there
are no such files having a shebang line.
Note that using "shfmt -f ." to find shell scripts is not an option, as it
skips dot-files (e.g. hack/make/.binary) even with --detect=all, and
scripts with a non-standard shebang (contrib/init/openrc/docker.initd).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>