Check GOBIN on make install

[bentito]

Description of the change:
Add checking for set GOBIN on make install

Motivation for the change:
With this change we catch situation where GOBIN isn't defined and make install silently fails.

$ unset GOBIN
$ make install
Error: GOBIN is not set
make: *** [Makefile:75: install] Error 1
$ source ~/.bash_profile
$ echo $GOBIN/
/usr/local/go/bin/
$ make install
go install -gcflags "all=-trimpath=/home/user1" -asmflags "all=-trimpath=/home/user1" -ldflags " -X 'github.com/operator-framework/operator-sdk/internal/version.Version=v1.32.0+git' -X 'github.com/operator-framework/operator-sdk/internal/version.GitVersion=v1.32.0-6-g034aef67-dirty' -X 'github.com/operator-framework/operator-sdk/internal/version.GitCommit=034aef6779729a30ac3d716f93a01824ed8dd3c7' -X 'github.com/operator-framework/operator-sdk/internal/version.KubernetesVersion=v1.26.0' -X 'github.com/operator-framework/operator-sdk/internal/version.ImageVersion=v1.32.0' "  ./cmd/{operator-sdk,helm-operator}
$ which operator-sdk
/usr/local/go/bin/operator-sdk

proposed as a fix for #6627

Checklist

If the pull request includes user-facing changes, extra documentation is required:

• Add a new changelog fragment in changelog/fragments (see changelog/fragments/00-template.yaml)
• Add or update relevant sections of the docs website in website/content/en/docs

[grokspawn]

Hey @bentito would you please rebase this PR and signoff the commits?

[bentito]

Hey @bentito would you please rebase this PR and signoff the commits?

okay rebased, signed off, DCO passing now