Set CommitDate in goreleaser archives

[alexbozhenko]

Follow up to #6299
The modification time of LICENSE and README.md in the archive is the one when the job https://github.com/nats-io/nats-server/actions/runs/13816873025/job/38652255585 checked out the code:

wget https://github.com/nats-io/nats-server/releases/download/v2.11.0-RC.3/nats-server-v2.11.0-RC.3-linux-amd64.tar.gz
tar -xvf nats-server-v2.11.0-RC.3-linux-amd64.tar.gz
ll nats-server-v2.11.0-RC.3-linux-amd64
total 16080
drwxr-xr-x  2 alex alex      100 Mar 12 12:58 .
drwxrwxrwt 48 root root     1280 Mar 12 12:57 ..
-rw-r--r--  1 alex alex    11357 Mar 12 09:54 LICENSE
-rwxr-xr-x  1 alex alex 16442017 Mar 12 09:43 nats-server
-rw-r--r--  1 alex alex     4404 Mar 12 09:54 README.md

And that works as designed: actions/checkout#364 (comment)

Those timestamps make archive not reproducible. Fix it by setting to commitDate.

Test plan:

 touch LICENSE README.md

goreleaser  release --snapshot --clean -f .goreleaser.yml

Timestamp of all the files is the same(commit date), making archives reproducible:

tar -xvf dist/nats-server-v2.11.0-RC.3-linux-amd64.tar.gz
# ll nats-server-v2.11.0-RC.3-linux-amd64/
total 16088
drwxr-xr-x  2 alex alex     4096 Mar 12 12:53 .
drwxr-xr-x 16 alex alex     4096 Mar 12 12:53 ..
-rw-r--r--  1 alex alex    11357 Mar 12 09:43 LICENSE
-rwxr-xr-x  1 alex alex 16442017 Mar 12 09:43 nats-server
-rw-r--r--  1 alex alex     4404 Mar 12 09:43 README.md

Signed-off-by: Alex Bozhenko alex@synadia.com

[alexbozhenko]

cc @neilalexander

[neilalexander]

LGTM, thanks!