docs: correct stale command example output

[abhinavgautam01]

Closes git-pkgs/git-pkgs#281
Updates the git pkgs stale --days=365 example in the Stale documentation to match the current CLI text output.

The previous example showed an obsolete table header and commit column. The command now prints each dependency as:

$ git pkgs stale --days=365
left-pad             2.0.1  (1842 days)  2019-03-15
moment               1.1.0  (1395 days)  2020-06-01
request              5.3.2  (1107 days)  2021-01-10

[andrew]

Thanks!