feat: mod push add examples dir also mark generator executable

[adohe]

What type of PR is this?

/kind feature

What this PR does / why we need it:

mod push add example dir also mark generator executable

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Additional documentation e.g., design docs, usage docs, etc.:

[coveralls]

Pull Request Test Coverage Report for Build 8433109945

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 79 (0.0%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 58.109%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/cmd/mod/mod_push.go	0	3	0.0%
pkg/cmd/generate/generator/generator.go	0	4	0.0%
pkg/util/io/file.go	0	17	0.0%
pkg/util/io/dir.go	0	55	0.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/cmd/generate/generator/generator.go	2	0.0%

Totals
Change from base Build 8432448062:	-0.2%
Covered Lines:	7356
Relevant Lines:	12659

---

💛 - Coveralls

[liu-hm19]

lgtm