Remove unsupported DJ versions in dependabot checks

Author: vmcj

.github/dependabot.yml

@@ -8,42 +8,6 @@ updates:
     versioning-strategy: increase-if-necessary
     allow:
         - dependency-type: "all"
-  - package-ecosystem: "composer"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-    open-pull-requests-limit: 0
-    versioning-strategy: lockfile-only
-    allow:
-        - dependency-type: "all"
-    target-branch: "7.3"
-  - package-ecosystem: "composer"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-    open-pull-requests-limit: 0
-    versioning-strategy: lockfile-only
-    allow:
-        - dependency-type: "all"
-    target-branch: "8.0"
-  - package-ecosystem: "composer"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-    open-pull-requests-limit: 0
-    versioning-strategy: lockfile-only
-    allow:
-        - dependency-type: "all"
-    target-branch: "8.1"
-  - package-ecosystem: "composer"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-    open-pull-requests-limit: 0
-    versioning-strategy: lockfile-only
-    allow:
-        - dependency-type: "all"
-    target-branch: "8.2"
   - package-ecosystem: "composer"
     directory: "/"
     schedule: