Fix the ability to use "bashbrew.sh" from any working directory

Author: tianon

bashbrew.sh

@@ -7,6 +7,9 @@ dir="$(readlink -f "$BASH_SOURCE")"
 dir="$(dirname "$dir")"
 
 export GO111MODULE=on
-go build -o bin/bashbrew -mod vendor ./cmd/bashbrew > /dev/null
+(
+	cd "$dir"
+	go build -o bin/bashbrew -mod vendor ./cmd/bashbrew > /dev/null
+)
 
 exec "$dir/bin/bashbrew" "$@"