Delete tag API (#13358)

* Delete tag API

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Wording

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Add conflict response and fix API tests

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix other test

Signed-off-by: jolheiser <john.olheiser@gmail.com>

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

templates/swagger/v1_json.tmpl

@@ -7834,6 +7834,47 @@
             "$ref": "#/responses/notFound"
           }
         }
+      },
+      "delete": {
+        "tags": [
+          "repository"
+        ],
+        "summary": "Delete a release tag",
+        "operationId": "repoDeleteReleaseTag",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the tag to delete",
+            "name": "tag",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "204": {
+            "$ref": "#/responses/empty"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          },
+          "409": {
+            "$ref": "#/responses/conflict"
+          }
+        }
       }
     },
     "/repos/{owner}/{repo}/releases/{id}": {
@@ -16249,6 +16290,9 @@
         "$ref": "#/definitions/WatchInfo"
       }
     },
+    "conflict": {
+      "description": "APIConflict is a conflict empty response"
+    },
     "empty": {
       "description": "APIEmpty is an empty response"
     },