docker: Libervia revision can now be specified:

Using the `DOCKER_LIBERVIA_REV` environment variable, backend (and related repos) revision
can now be specified. By default (variable empty or not set), the current `tip` version is
used, and `dev` is used for tagging. If the variable is set, the revision will be used and
used for tagging the image.

docker/docker-compose-e2e.yml

@@ -38,8 +38,11 @@ services:
       LIBERVIA_PUBSUB_XMPP_PWD: test_e2e
 
   backend:
-    image: libervia/backend:dev-e2e
-    build: backend-dev-e2e
+    image: libervia/backend:${DOCKER_LIBERVIA_REV:-dev}-e2e
+    build:
+      context: backend-dev-e2e
+      args:
+        REVISION: ${DOCKER_LIBERVIA_REV:-}
     environment:
       LIBERVIA_TEST_ENV_E2E: "1"
       LIBERVIA_TEST_ENV_E2E_WEB: "1"
@@ -54,8 +57,11 @@ services:
           - libervia-backend.test
 
   web:
-    image: libervia/web:dev-e2e
-    build: libervia-web-dev-e2e
+    image: libervia/web:${DOCKER_LIBERVIA_REV:-dev}-e2e
+    build:
+      context: libervia-web-dev-e2e
+      args:
+        REVISION: ${DOCKER_LIBERVIA_REV:-}
     depends_on:
       - backend
     environment: