build: remove obsolete mergify rules for 1.8 and 1.9

The backports to old branches are not supported or
have no need for automation, so we remove the
mergify rules for the super old releases.

Signed-off-by: Travis Nielsen <tnielsen@redhat.com>

.mergify.yml

@@ -15,86 +15,6 @@ pull_request_rules:
       comment:
         message: Hi @{{author}}, this pull request was opened against a release branch, is it expected? Normally patches should go in the master branch first and then be backported to release branches.
 
-  # release-1.8 branch
-  - name: automerge backport release-1.8
-    conditions:
-      - author=mergify[bot]
-      - base=release-1.8
-      - label!=do-not-merge
-      - "status-success=DCO"
-      - "check-success=canary"
-      - "check-success=unittests"
-      - "check-success=golangci-lint"
-      - "check-success=codegen"
-      - "check-success=lint"
-      - "check-success=modcheck"
-      - "check-success=pvc"
-      - "check-success=pvc-db"
-      - "check-success=pvc-db-wal"
-      - "check-success=encryption-pvc"
-      - "check-success=encryption-pvc-db"
-      - "check-success=encryption-pvc-db-wal"
-      - "check-success=encryption-pvc-kms-vault-token-auth"
-      - "check-success=encryption-pvc-kms-vault-k8s-auth"
-      - "check-success=lvm-pvc"
-      - "check-success=multi-cluster-mirroring"
-      - "check-success=rgw-multisite-testing"
-      - "check-success=TestCephSmokeSuite (v1.16.15)"
-      - "check-success=TestCephSmokeSuite (v1.22.2)"
-      - "check-success=TestCephHelmSuite (v1.16.15)"
-      - "check-success=TestCephHelmSuite (v1.22.2)"
-      - "check-success=TestCephMultiClusterDeploySuite (v1.22.2)"
-      - "check-success=TestCephUpgradeSuite (v1.16.15)"
-      - "check-success=TestCephUpgradeSuite (v1.22.2)"
-    actions:
-      merge:
-        method: merge
-      dismiss_reviews: {}
-      delete_head_branch: {}
-
-  # release-1.9 branch
-  - name: automerge backport release-1.9
-    conditions:
-      - author=mergify[bot]
-      - base=release-1.9
-      - label!=do-not-merge
-      - "status-success=DCO"
-      - "check-success=canary"
-      - "check-success=unittests"
-      - "check-success=golangci-lint"
-      - "check-success=codegen"
-      - "check-success=codespell"
-      - "check-success=lint"
-      - "check-success=modcheck"
-      - "check-success=Shellcheck"
-      - "check-success=yaml-linter"
-      - "check-success=lint-test"
-      - "check-success=gen-rbac"
-      - "check-success=crds-gen"
-      - "check-success=pvc"
-      - "check-success=pvc-db"
-      - "check-success=pvc-db-wal"
-      - "check-success=encryption-pvc"
-      - "check-success=encryption-pvc-db"
-      - "check-success=encryption-pvc-db-wal"
-      - "check-success=encryption-pvc-kms-vault-token-auth"
-      - "check-success=encryption-pvc-kms-vault-k8s-auth"
-      - "check-success=lvm-pvc"
-      - "check-success=multi-cluster-mirroring"
-      - "check-success=rgw-multisite-testing"
-      - "check-success=TestCephSmokeSuite (v1.17.17)"
-      - "check-success=TestCephSmokeSuite (v1.23.0)"
-      - "check-success=TestCephHelmSuite (v1.17.17)"
-      - "check-success=TestCephHelmSuite (v1.23.0)"
-      - "check-success=TestCephMultiClusterDeploySuite (v1.23.0)"
-      - "check-success=TestCephUpgradeSuite (v1.17.17)"
-      - "check-success=TestCephUpgradeSuite (v1.23.0)"
-    actions:
-      merge:
-        method: merge
-      dismiss_reviews: {}
-      delete_head_branch: {}
-
   # release-1.10 branch
   - name: automerge backport release-1.10
     conditions:
@@ -354,24 +274,6 @@ pull_request_rules:
       dismiss_reviews: {}
       delete_head_branch: {}
 
-  # release-1.8 branch
-  - actions:
-      backport:
-        branches:
-          - release-1.8
-    conditions:
-      - label=backport-release-1.8
-    name: backport release-1.8
-
-  # release-1.9 branch
-  - actions:
-      backport:
-        branches:
-          - release-1.9
-    conditions:
-      - label=backport-release-1.9
-    name: backport release-1.9
-
   # release-1.10 branch
   - actions:
       backport: