Cleanup cosign-installer membership

Add two cosign maintainers to the repo, remove inactive member

Also removed unused team

Signed-off-by: Hayden Blauzvern <hblauzvern@google.com>

github-sync/github-data/teams.yaml

@@ -41,9 +41,6 @@ teams:
   - name: gitsign-codeowners
     privacy: closed
     description: ""
-  - name: git-verifier-codeowners
-    privacy: closed
-    description: ""
   - name: helm
     privacy: closed
     description: Helm Maintenance

github-sync/github-data/users.yaml

@@ -213,6 +213,8 @@ users:
         role: member
       - name: cosign-codeowners
         role: member
+      - name: cosign-installer-codeowners
+        role: member
       - name: fulcio-codeowners
         role: member
       - name: rekor-monitor-codeowners
@@ -333,8 +335,6 @@ users:
         role: maintainer
       - name: fulcio-codeowners
         role: maintainer
-      - name: git-verifier-codeowners
-        role: maintainer
       - name: helm-sigstore-codeowners
         role: maintainer
       - name: policy-controller-codeowners
@@ -383,13 +383,6 @@ users:
         role: member
       - name: cosign-codeowners
         role: member
-  - username: mbestavros
-    role: member
-    teams:
-      - name: cosign-installer-codeowners
-        role: member
-      - name: git-verifier-codeowners
-        role: member
   - username: mdunbavan
     role: member
     teams:
@@ -516,6 +509,8 @@ users:
         role: member
       - name: cosign-codeowners
         role: member
+      - name: cosign-installer-codeowners
+        role: member
       - name: protobuf-specs-codeowners
         role: member
       - name: rekor-monitor-codeowners