chore: fix tracking of Hugo version by updatecli by removing YAML anchor in Docker Compose

[dduportal]

Fixup of #551

This PR removes the Docker Compose file YAML anchors as not supported by updatecli (creates PR with garbage in the YAML file making it unparseable).

It updates the updatecli manifest accordingly, along with the GHA workflow used to verify hugo.

Tested the updatecli manifest (as the check will fail in the PR) locally and got the following result:

diff --git a/docker-compose.yaml b/docker-compose.yaml
index 3cea750..5ac4177 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -1,6 +1,6 @@
 services:
   status:
-    image: hugomods/hugo:ci-0.128.0
+    image: hugomods/hugo:ci-0.138.0
     volumes:
       - .:/src
     ports:
diff --git a/netlify.toml b/netlify.toml
index 623ac48..ce68f10 100644
--- a/netlify.toml
+++ b/netlify.toml
@@ -4,7 +4,7 @@
     functions = "functions"
 
 [build.environment]
-    HUGO_VERSION = "0.128.0"
+    HUGO_VERSION = "0.138.0"
 
 [[headers]]
     for = "/*.json"
@@ -14,7 +14,7 @@
 [context.production.environment]
     HUGO_ENV = "production"
     NODE_ENV = "production"
-    HUGO_VERSION = "0.128.0"
+    HUGO_VERSION = "0.138.0"
 
 [context.deploy-preview]
     command = "hugo --gc --minify --buildFuture -b $DEPLOY_PRIME_URL"