feat(storage): expose purgeCache

[mandarini]

Authored by @mansueli
Moved from here: supabase/storage-js#229

What kind of change does this PR introduce?

The goal is to expose the purgeCache operation from the API to the client libraries.

        "/cdn/{bucketName}/{wildcard}": {
            "delete": {
                "summary": "Purge cache for an object",
                "tags": [
                    "object"
                ],
                "parameters": [
                    {
                        "schema": {
                            "type": "string"
                        },
                        "example": "avatars",
                        "in": "path",
                        "name": "bucketName",
                        "required": true
                    },
                    {
                        "schema": {
                            "type": "string"
                        },
                        "example": "folder/cat.png",
                        "in": "path",
                        "name": "*",
                        "required": true
                    },
                    {
                        "schema": {
                            "type": "string"
                        },
                        "example": "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZS1kZW1vIiwicm9sZSI6ImFub24ifQ.625_WdcF3KHqz5amU0x2X5WWHP-OEs_4qj0ssLNHzTs",
                        "in": "header",
                        "name": "authorization",
                        "required": true
                    }
                ],
                "responses": {
                    "200": {
                        "description": "Successful response",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "description": "Successful response",
                                    "type": "object",
                                    "properties": {
                                        "message": {
                                            "type": "string",
                                            "examples": [
                                                "success"
                                            ]
                                        }
                                    }
                                }
                            }
                        }
                    },
                    "4XX": {
                        "description": "Error response",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "description": "Error response",
                                    "$ref": "#/components/schemas/def-1"
                                }
                            }
                        }
                    }
                }
            }
        },

What is the current behavior?

There's no support this in the client libraries.

What is the new behavior?

The goal is to allow this to be exposed in the supabase-js client e.g:

storage.from(BUCKET_ID).purgeCache('test.png')

[coveralls]

coverage: 95.455% (+13.0%) from 82.5%
when pulling c33f0ac on feat/expose-purgeCache
into 2d0bd77 on master.

[github-actions]

This PR has been marked as stale because it has not had activity for 90 days.
It will be closed in 14 days if no further activity occurs.

Please rebase and update if this is still needed.