Fix packages name and binary in the packages

[cpanato]

Summary

In the PR #1683 we replaced the name to be just cosign but that affects the multi-arch packages, so at the end of the process we just have one available and miss others.

Changing that fixes the issue and we will have one for each arch.
The other issue was the binary name which is not cosign but instead cosign-linux-amd64 (in this case for amd64), this is because we build the binary and generate with that name, but in the package when installed should be just cosign , adding symlink fixes that

Rehearsal : https://github.com/cpanato/cosign/releases/tag/v99.99.01

The snippet below shows the closing after installing the change from this PR amd64 ubuntu machine

root@ubuntu-s-1vcpu-1gb-amd-fra1-01:~# which cosign
/usr/bin/cosign
root@ubuntu-s-1vcpu-1gb-amd-fra1-01:~# cosign version
  ______   ______        _______. __    _______ .__   __.
 /      | /  __  \      /       ||  |  /  _____||  \ |  |
|  ,----'|  |  |  |    |   (----`|  | |  |  __  |   \|  |
|  |     |  |  |  |     \   \    |  | |  | |_ | |  . `  |
|  `----.|  `--'  | .----)   |   |  | |  |__| | |  |\   |
 \______| \______/  |_______/    |__|  \______| |__| \__|
cosign: A tool for Container Signing, Verification and Storage in an OCI registry.

GitVersion:    v99.99.00-dirty
GitCommit:     8def7341d261c2d831a4b06c12cd5ff952a458b5
GitTreeState:  dirty
BuildDate:     2022-04-11T07:45:56Z
GoVersion:     go1.18
Compiler:      gc
Platform:      linux/amd64

root@ubuntu-s-1vcpu-1gb-amd-fra1-01:~# cd /usr/bin/
root@ubuntu-s-1vcpu-1gb-amd-fra1-01:/usr/bin# ls -la co*
....
lrwxrwxrwx 1 root root       27 Apr 11 08:30 cosign -> /usr/bin/cosign-linux-amd64
-rwxr-xr-x 1 root root 91780356 Apr 11 07:45 cosign-linux-amd64
root@ubuntu-s-1vcpu-1gb-amd-fra1-01:/usr/bin#

Ticket Link

Fixes #1733

Release Note

Fix packages name and binary in the packages