Wrong URL path formation at variable edition/deleting

[appsec-igm-sbf]

https://github.com/PyGithub/PyGithub/blob/dc37d5c1852a1c2f7083118adeda22760d575420/github/Variable.py#L99C25-L99C55

Description:

The self.url is already actions/variables/{variable_name} and does not need to repeat the path as it is in the code.

Evidences:

Malformed URL:
PATCH https://api.github.com/repos/grupo-sbf/pci-api/actions/variables/CX_ADDITIONAL_PARAMETERS/actions/variables/CX_ADDITIONAL_PARAMETERS

{ "headers": { "Authorization": "token (oauth token removed)", "User-Agent": "PyGithub/Python", "Content-Type": "application/json" }, "data": { "name": "CX_ADDITIONAL_PARAMETERS", "value": "oie" }, "status": 404, "responseHeaders": { "server": "GitHub.com", "date": "Fri, 10 Nov 2023 16:12:00 GMT", "content-type": "application/json; charset=utf-8", "transfer-encoding": "chunked", "x-oauth-scopes": "admin:org_hook, codespace, project, read:discussion, read:org, read:packages, read:user, repo, user:email, workflow", "x-accepted-oauth-scopes": "repo", "github-authentication-token-expiration": "2023-12-01 13:25:29 UTC", "x-github-media-type": "github.v3; format=json", "x-github-api-version-selected": "2022-11-28", "x-ratelimit-limit": "5000", "x-ratelimit-remaining": "4973", "x-ratelimit-reset": "1699635340", "x-ratelimit-used": "27", "x-ratelimit-resource": "core", "access-control-expose-headers": "ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset", "access-control-allow-origin": "*", "strict-transport-security": "max-age=31536000; includeSubdomains; preload", "x-frame-options": "deny", "x-content-type-options": "nosniff", "x-xss-protection": "0", "referrer-policy": "origin-when-cross-origin, strict-origin-when-cross-origin", "content-security-policy": "default-src 'none'", "vary": "Accept-Encoding, Accept, X-Requested-With", "content-encoding": "gzip", "x-github-request-id": "20B6:21F720:12149D6:1368BCF:654E5650" }, "error": { "message": "Not Found", "documentation_url": "https://docs.github.com/rest" } }