Investigate CI Rate Limiting

[donn]

The CI has failed intermittently as of late (most notably on the Mac nix build,) as it turns out this is because the onslaught of volare enables causes the file in question to be rate-limited.

[donn]

Ultimately resolved in #190 with the cumulative changes in Volare 0.12.3.

[Kodalem]

EDIT: Moved this to #654

This bug has popped up again, here is the traceback:

[nix-shell:~/openlane2/chip-design-intro/lab-input/lab1]$ openlane config.json
Version 0fe599b2afb6708d281543108caf8310912f54af not found locally, attempting to download…
Traceback (most recent call last):
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/volare/manage.py", line 181, in fetch
    release_link_list = version_object.get_release_links(
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/volare/common.py", line 192, in get_release_links
    release = github.get_release_links(f"{self.pdk}-{self.name}", session)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/volare/github.py", line 177, in get_release_links
    return session.api(volare_repo, f"/releases/tags/{release}", "get")
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/volare/github.py", line 140, in api
    req.raise_for_status()
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/httpx/_models.py", line 761, in raise_for_status
    raise HTTPStatusError(message, request=request, response=self)
httpx.HTTPStatusError: Client error '403 rate limit exceeded' for url 'https://api.github.com/repos/efabless/volare/releases/tags/sky130-0fe599b2afb6708d281543108caf8310912f54af'
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/403

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/nix/store/2yp37vk4f3rm7z0cxqx0al39iq7qj02i-python3.11-openlane-2.3.3/bin/.openlane-wrapped", line 9, in <module>
    sys.exit(cli())
             ^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/openlane/flows/cli.py", line 444, in pdk_resolve_wrapper
    version = volare.fetch(
              ^^^^^^^^^^^^^
  File "/nix/store/0qj3x1yif58v3dcbq3smm2mjd4vksvaq-python3-3.11.9-env/lib/python3.11/site-packages/volare/manage.py", line 250, in fetch
    raise RuntimeError(
RuntimeError: Failed to obtain 0fe599b2afb6708d281543108caf8310912f54af remotely: <Response [403 rate limit exceeded]>.