ci(commitlint): add local hook to enforce commit convention

Co-authored-by: Soha Alboghdady <[email protected]>
Co-authored-by: Raghunath Deshpande <[email protected]>

.hooks/README.md

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+# Git Hooks
+
+Run conventional commit checks locally without any tool installation
+
+## Usage
+
+Adjust the git commit hook configuration as follows, from the root directory of pcap-release:
+
+```shell
+git config core.hooksPath .hooks
+```
+
+Please note that any hooks you had in other directories may not work.
+
+Alternatively you can also soft-link the commit-msg script:
+
+```shell
+ln -s .hooks/commit-msg .git/hooks/commit-msg
+```
+
+This invocation will fail if you have a commit-msg hook already, in order to not break existing hooks.

.hooks/commit-msg

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+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# use commitlint with its full config if available
+if command -v commitlint >/dev/null && commitlint -v >/dev/null; then
+  # Find base directory (script_location/..)
+  COMMITLINT_CONFIG="$(realpath "$(dirname "$0")/..")/commitlint.config.js"
+  # execute commitlint only if the commitlint config exists
+  [[ -f "$COMMITLINT_CONFIG" ]] && exec commitlint --edit "$1" --verbose --config "$COMMITLINT_CONFIG"
+fi
+
+# Configuration
+
+# list of allowed commit types, space separated
+TYPES="fix feat dep ci doc refactor test"
+# scope length
+SCOPE_LENGTH=25
+# commit subject length
+SUBJECT_LENGTH=70
+
+# Logic
+first_line=$(head -n1 "$1")
+conv_commit_msg="^(${TYPES// /|})(\(.{1,$SCOPE_LENGTH}\))?(!?): (.{1,$SUBJECT_LENGTH})\$"
+
+_print_convention() {
+  echo "ERROR: Commit message does not confirm to commit conventions."
+  echo "       ----"
+  sed 's/^/     > /' "$1"
+  echo
+  echo "Rules: type(scope)!: commit subject"
+  echo "     - type: must be one of: ${TYPES// /, }"
+  echo "     - scope: (optional) arbitrary text: "
+  echo "     - !: breaking change indicator. Body MUST contain 'breaking-change:' header (case in-sensitive)"
+}
+
+# trap will be fired when the script exits. It will exit if any of the commands, including the grep below, fail.
+trap '_print_convention "$1"' EXIT
+
+# check that the first line conforms to the convention pattern
+grep -qE "$conv_commit_msg" <<< "$first_line"
+
+# if there is a !, indicating breaking change, ensure that there is a "breaking-change:" header.
+if [[ "$(sed -nE "s/$conv_commit_msg/\3/p" <<<"$first_line")" == "!" ]]; then
+  grep -qiE "^breaking(-| )change: .+" "$1"
+fi
+
+# All rules passed. Disable _print_convention printing
+trap "" EXIT