Increase httputil.MaxRequestDuration to 30s (bazelbuild#257)

The old value was too low to actually allow four retries.

No longer get incompatible flags from GitHub (bazelbuild#248)

We're turning down the tracking issues for incompatible flags. As a result, `bazelisk --migrate` should simply test all incompatible flags that are present in the Bazel binary.

Please note that the new implementation is as technically incorrect as the previous one, given that it simply tests a list of incompatible flags without making sure that they're implemented for the actual Bazel command that is being executed.
However, in reality this hasn't been a problem since we started using --migrate on Bazel CI.

Fix bazelbuild#219: Provide ARM releases (for Mac M1) (bazelbuild#242)

* Fix bazelbuild#219: Provide ARM releases (for Mac M1)

With these changes, Bazelisk binaries for darwin-arm64 will be built.

Additionally, we build a universal Mac binary that can be used on amd64
and arm64 Macs and runs natively on either.

* Only build the universal binary on macOS

Fix bug in last_rc logic (bazelbuild#237)

We're going to upload rolling releases to GCS, too. While Bazelisk continues to download rolling releases from GitHub, the presence of rolling releases on GCS actually broke the resolution logic for "last_rc". This commit fixes the problem and adds test coverage for similar scenarios.

Update npm instructions in build.sh.

Ensure Go 1.11 compatibility... (bazelbuild#215)

...by replacing strings.ReplaceAll() with strings.Replace().

Progress towards bazelbuild#206

Discard releases when reading candidates (bazelbuild#190)

This commit fixes two related problems: when version equaled "last_rc", Bazelisk-Go would not discard release versions, and it would return the "release" suffix as part of the version label.

Fixes bazelbuild#189

Fix accidental variable shadowing that broke version resolution. (baz…

…elbuild#186)

Fixes bazelbuild#185

Fix documentation about release servers (bazelbuild#184)

In most cases Bazel binaries are fetched from GCS now, with the exception of forks (still on Github).

Fix BUILD files to correctly inject release version