script: use go install for goreleaser

[mmcloughlin]

The existing install script appears to be broken on Mac:

m1:addchain mbm$ ./script/bootstrap
...
+ curl -sfL https://install.goreleaser.com/github.com/goreleaser/goreleaser.sh
+ sh -s -- -b /Users/mbm/Development/gopath/bin v0.177.0
goreleaser/goreleaser crit uname_arch_check 'arm64' got converted to 'all' which is not a GOARCH value.  Please file bug report at https://github.com/client9/shlib

This install method was also recently removed from the goreleaser documentation:

goreleaser/goreleaser@7ddcfb0

[codecov-commenter]

Codecov Report

Merging #122 (5a8d982) into master (881e229) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #122   +/-   ##
=======================================
  Coverage   73.05%   73.05%           
=======================================
  Files          30       30           
  Lines        1874     1874           
=======================================
  Hits         1369     1369           
  Misses        445      445           
  Partials       60       60           

Flag	Coverage Δ
stress	?
unittests	73.05% <ø> (ø)

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