Cheer up shellcheck

ci/lint.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
-cd ${0%/*}/..
+cd "${0%/*}"/.. || exit 1
 if [ -x "$(command -v shellcheck)" ]; then
-	GLOBIGNORE="node_modules" shellcheck -e2012 **/*.sh
+	GLOBIGNORE="node_modules" shellcheck -e2012 ./**/*.sh
 else
 	echo "Warning: shellcheck is not installed, skipping shell scripts"
 fi

ci/mozilla.sh

@@ -1,4 +1,4 @@
 #! /bin/sh
 yarn run build --no-native
-cd ${0%/*}/../build
+cd "${0%/*}"/../build || exit 1
 "$(yarn bin)/web-ext" lint

ci/unit.sh

@@ -1,4 +1,4 @@
 #! /bin/sh
-cd ${0%/*}
+cd "${0%/*}" || exit
 yarn run build --no-native
 "$(yarn bin)/jest" src