ci (docker.yml): fix taskfile interpolation

Author: pythoninthegrass

{{cookiecutter.project_slug}}/taskfiles/docker.yml

@@ -3,19 +3,17 @@ version: "3.0"
 set: ['e', 'u', 'pipefail']
 shopt: ['globstar']
 
-env:
-  BUILD: "{{.TLD}}/bin/build.sh"
-  COMPOSE_FILE: "{{.TLD}}/docker-compose.yml"
-  DOCKERFILE: "{{.TLD}}/Dockerfile"
-  PLATFORM:
-    sh: "echo ${PLATFORM:-linux/arm64/v8}"
-  REGISTRY:
-    sh: "echo ${REGISTRY:-ghcr.io}"
-  USER_NAME:
-    sh: "echo ${USER_NAME:-pythoninthegrass}"
-  SERVICE: "mvp"
-  VERSION:
-    sh: "echo ${VERSION:-latest}"
+# env:
+
+vars:
+  COMPOSE_FILE: '{{.COMPOSE_FILE | default (printf "%s/docker-compose.yml" .ROOT_DIR)}}'
+  COMPOSE_REMOVE_ORPHANS: '{{.COMPOSE_REMOVE_ORPHANS | default "true"}}'
+  DOCKERFILE: '{{.DOCKERFILE | default (printf "%s/Dockerfile" .ROOT_DIR)}}'
+  ARCH: '{{.ARCH | default "linux/amd64"}}'
+  REGISTRY: '{{.REGISTRY | default "ghcr.io"}}'
+  USER_NAME: '{{.USER_NAME | default "pythoninthegrass"}}'
+  SERVICE: '{{.SERVICE | default "mvp"}}'
+  VERSION: '{{.VERSION | default "latest"}}'
 
 tasks:
   net: