Add git diff driver for gpg-encrypted files (#558)

Author: raxod502

git/.gitconfig

@@ -29,6 +29,9 @@
 	mnemonicprefix = true
 	renames = copies
 	submodule = log
+[diff "gpg"]
+	binary = true
+	textconv = gpg -d --quiet --yes --compress-algo=none --no-encrypt-to --batch --use-agent
 [init]
 	defaultBranch = main
 [merge]

scripts/check-line-length.bash

@@ -6,6 +6,7 @@ set -o pipefail
 find=(
     find .
     -name .git -prune -o
+    -name .gitconfig -o
     -name "*.elc" -o
     -type f -print
 )