Revert "Replace . with $PWD"

This reverts commit 892780d1.
$PWD does not work when deploying as a Swarm stack.

sample..env

@@ -2,7 +2,7 @@
 ## Project name
 COMPOSE_PROJECT_NAME=vcs
 
-# Repository folder (default: $PWD)
+# Repository folder (default: .)
 GL_HOME=
 
 # GitLab URL

sample.docker-compose.yml

@@ -8,9 +8,9 @@ services:
     ports:
       - "${GITLAB_SHELL_SSH_PORT:-10022}:22"
     volumes:
-      - ${GL_HOME:-$PWD}/gitlab/config:/etc/gitlab
-      - ${GL_HOME:-$PWD}/gitlab/logs:/var/log/gitlab
-      - ${GL_HOME:-$PWD}/gitlab/data:/var/opt/gitlab
+      - ${GL_HOME:-.}/gitlab/config:/etc/gitlab
+      - ${GL_HOME:-.}/gitlab/logs:/var/log/gitlab
+      - ${GL_HOME:-.}/gitlab/data:/var/opt/gitlab
     labels:
       - traefik.enable=true
       - traefik.docker.network=webproxy
@@ -165,7 +165,7 @@ services:
     image: gitlab/gitlab-runner
     restart: always
     volumes:
-      - ${GL_HOME:-$PWD}/gitlab-runner/config:/etc/gitlab-runner
+      - ${GL_HOME:-.}/gitlab-runner/config:/etc/gitlab-runner
       - /var/run/docker.sock:/var/run/docker.sock
 
   gitlab-smtp: