sysadm/issue-templates: Set and fix milestone and labels

That many actions less to do when creating a new task.

.gitlab/issue_templates/deploy-new-stack-in-production.md

 /title production: Deploy new <project> stack
 
-/milestone %<milestone>
+/milestone %"Extend archive coverage [Roadmap - Collect]"
+
+/labels ~"activity::Deployment"
 
-/label ~"activity::deployment"
 
 - [ ] [swh-charts](https://gitlab.softwareheritage.org/swh/infra/ci-cd/swh-charts/-/blob/production/swh/values/production.yaml?ref_type=heads#L126): Checkout production branch
 - [ ] [swh-charts](https://gitlab.softwareheritage.org/swh/infra/ci-cd/swh-charts/-/blob/production/swh/values/production.yaml?ref_type=heads#L143): Adapt values to reference the new lister and loader (equivalent to what was done for staging)

.gitlab/issue_templates/deploy-new-stack-in-staging.md

 /title staging: Deploy new <project> stack
 
-/milestone %<milestone>
+/milestone %"Extend archive coverage [Roadmap - Collect]"
+
+/labels ~"activity::Deployment"
 
-/label ~"activity::deployment"
 
 - [ ] [swh-apps](https://gitlab.softwareheritage.org/swh/infra/swh-apps/-/tree/master/apps?ref_type=heads): Build image (if required)
 - [ ] [swh-charts](https://gitlab.softwareheritage.org/swh/infra/ci-cd/swh-charts/-/blob/staging/values-swh-application-versions.yaml?ref_type=heads): Reference new image (if required)

.gitlab/issue_templates/deploy-new-stack-version.md

 /title Deploy new <project> <version>
 
-/milestone %<milestone>
+/milestone %"MRO 2023"
+
+/labels ~"activity::Deployment"
+
 
-/label ~"activity::deployment"
 
 staging:
 - [ ] [swh-apps](https://gitlab.softwareheritage.org/swh/infra/swh-apps/-/tree/master/apps?ref_type=heads): Build image (if required because of new deps for example)

.gitlab/issue_templates/deploy-next-swh-version.md

@@ -2,7 +2,8 @@
 
 /milestone %"MRO 2023"
 
-/label ~"activity::deployment"
+/labels ~"activity::Deployment"
+
 
 Actions:
 - [ ] Tags all impacted modules

.gitlab/issue_templates/new-physical-server.md

@@ -2,6 +2,8 @@
 
 /milestone %"MRO 2023"
 
+/labels ~"activity::Deployment"
+
 Orders: <link to the mybox directory containing the order/delivery orders/...>
 
 Inventory: <link to the inventory page>