Graceful retry after API errors

[stigok]

If the GitHub credentials are invalid, the API will be spammed with requests until it will succeed again. That will probably never happen.

s	{"err": [{"error": "GET https://api.github.com/rate_limit: 401 Bad credentials []"}]}
1.7095442091525905e+09	warn	github store	github/github.go:247	failed to get rate limit status	{"err": [{"error": "GET https://api.github.com/rate_limit: 401 Bad credentials []"}]}
1.7095442091993673e+09	warn	github store	github/github.go:247	failed to get rate limit status	{"err": [{"error": "GET https://api.github.com/rate_limit: 401 Bad credentials []"}]}
1.7095442092015991e+09	warn	github store	github/github.go:247	failed to get rate limit status	{"err": [{"error": "GET https://api.github.com/rate_limit: 401 Bad credentials []"}]}
1.7095442092082374e+09	warn	github store	github/github.go:247	failed to get rate limit status	{"err": [{"error": "GET https://api.github.com/rate_limit: 401 Bad credentials []"}]}
1.7095442092203035e+09	warn	github store	github/github.go:247	failed to get rate limit status	{"err": [{"error": "GET https://api.github.com/rate_limit: 401 Bad credentials []"}]}

This might just be the rate limit checker

[stigok]

Other code paths seem to fail once and retry later on when they are next invoked

1.709544103457516e+09	error	terraform-registry/main.go:293	failed to reload GitHub store cache	{"err": [{"error": "GET https://api.github.com/search/repositories?per_page=100&q=org%3A%22nrkno%22+topic%3A%22terraform-module%22: 401 Bad credentials []"}]}