Makefile: use urfave_cli_no_docs for binaries that don't need it

[thaJeztah]

• relates to [v1] Add urfave_cli_no_docs build tag urfave/cli#1383
• follow-up to vendor: github.com/urfave/cli v1.22.9 and fix "verify-vendor" script #6997

(first commit is from #6997 - I'll rebase once that's merged)

We only need the ToMan() as part of the bin/gen-manpages binary, which
generates the man-pages; other binaries don't use this code, so we can
set the urfave_cli_no_docs build-tag to exclude cpuguy83/md2man and
russross/blackfriday (and other dependencies) from the binaries:

Before:

ls -lh bin
total 149M
-rwxr-xr-x 1 root root  49M May 27 10:12 containerd
-rwxr-xr-x 1 root root 6.1M May 27 10:13 containerd-shim
-rwxr-xr-x 1 root root 8.1M May 27 10:13 containerd-shim-runc-v1
-rwxr-xr-x 1 root root 8.2M May 27 10:13 containerd-shim-runc-v2
-rwxr-xr-x 1 root root  22M May 27 10:12 containerd-stress
-rwxr-xr-x 1 root root  26M May 27 10:11 ctr
-rwxr-xr-x 1 root root  30M May 27 10:14 gen-manpages

ls -l bin
total 151676
-rwxr-xr-x 1 root root 51280184 May 27 10:12 containerd
-rwxr-xr-x 1 root root  6332416 May 27 10:13 containerd-shim
-rwxr-xr-x 1 root root  8458240 May 27 10:13 containerd-shim-runc-v1
-rwxr-xr-x 1 root root  8536064 May 27 10:13 containerd-shim-runc-v2
-rwxr-xr-x 1 root root 22567160 May 27 10:12 containerd-stress
-rwxr-xr-x 1 root root 26873752 May 27 10:11 ctr
-rwxr-xr-x 1 root root 30508888 May 27 10:14 gen-manpages

After:

ls -lh bin
total 147M
-rwxr-xr-x 1 root root  49M May 27 10:26 containerd
-rwxr-xr-x 1 root root 6.1M May 27 10:26 containerd-shim
-rwxr-xr-x 1 root root 8.1M May 27 10:26 containerd-shim-runc-v1
-rwxr-xr-x 1 root root 8.2M May 27 10:26 containerd-shim-runc-v2
-rwxr-xr-x 1 root root  22M May 27 10:26 containerd-stress
-rwxr-xr-x 1 root root  26M May 27 10:26 ctr
-rwxr-xr-x 1 root root  30M May 27 10:27 gen-manpages

ls -l bin
total 149912
-rwxr-xr-x 1 root root 50930360 May 27 10:26 containerd
-rwxr-xr-x 1 root root  6332416 May 27 10:26 containerd-shim
-rwxr-xr-x 1 root root  8458240 May 27 10:26 containerd-shim-runc-v1
-rwxr-xr-x 1 root root  8536064 May 27 10:26 containerd-shim-runc-v2
-rwxr-xr-x 1 root root 22209144 May 27 10:26 containerd-stress
-rwxr-xr-x 1 root root 26523896 May 27 10:26 ctr
-rwxr-xr-x 1 root root 30508888 May 27 10:27 gen-manpages

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[kzys]

I didn't know I could specify build tags for dependencies... Is it namespaced?

[thaJeztah]

Afaik, build-tags are propagated to everything used in the build (so definitely also something to take into account in case a custom build-tag "conflicts" with build-tags defined by a dependency)

[thaJeztah]

@estesp ptal (I think I recall a comment from you once about the CLI always performing/loading some markdown code 😂 - I may mis-remember though)

[estesp]

LGTM