Merge pull request #2979 from lucas-clemente/pre-commit-hook

add some useful pre-commit hooks

.githooks/README.md

@@ -0,0 +1,8 @@
+# Git Hooks
+
+This directory contains useful Git hooks for working with quic-go.
+
+Install them by running
+```bash
+git config core.hooksPath .githooks
+```

.githooks/pre-commit

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+# Check that test files don't contain focussed test cases.
+errored=false
+for f in $(git diff --cached --name-only); do
+	if [[ $f != *_test.go ]]; then continue; fi
+	output=$(grep -n -e "FIt(" -e "FContext(" -e "FDescribe(" "$f")
+	if [ $? -eq 0 ]; then
+		echo "$f contains a focussed test:"
+		echo "$output"
+		echo ""
+		errored=true
+	fi
+done
+
+# Check that all files are properly gofumpt-ed.
+output=$(gofumpt -d $(git diff --cached --name-only))
+if [ -n "$output" ]; then
+	echo "Found files that are not properly gofumpt-ed."
+	echo "$output"
+	errored=true
+fi
+
+if [ "$errored" = true ]; then
+	exit 1
+fi