fix: remove hardcoded reference to github.com when using reusable remote workflows and remote actions

[shubhbapna]

fixes #1588

By removing reference to the hardcoded github.com and instead using serverURL from github context, we can start controlling where we clone these actions/workflows from. So for example if we want act to use ssh then we can simply pass the following option:

--env GITHUB_SERVER_URL=ssh://git@github.com

Moreover, I noticed that for reusable workflows we are cloning the repositories in a directory named - {owner}-{repo}-.github-workflows-{filename}@{ref}. However if we change this directory name to be {owner}-{repo}@{ref}, we will be able to reduce the number of clones act will make when using multiple reusable workflows from the same repository.

[codecov]

Codecov Report

Merging #1784 (308edcd) into master (4989f44) will increase coverage by 1.27%.
The diff coverage is 65.22%.

@@            Coverage Diff             @@
##           master    #1784      +/-   ##
==========================================
+ Coverage   61.22%   62.50%   +1.27%     
==========================================
  Files          46       51       +5     
  Lines        7141     8067     +926     
==========================================
+ Hits         4372     5042     +670     
- Misses       2462     2645     +183     
- Partials      307      380      +73     

Impacted Files	Coverage Δ
pkg/common/outbound_ip.go	0.00% <0.00%> (ø)
pkg/container/docker_cli.go	82.23% <ø> (ø)
pkg/container/docker_logger.go	52.08% <ø> (ø)
pkg/container/docker_pull.go	33.33% <ø> (ø)
pkg/container/docker_run.go	13.58% <0.00%> (-0.01%)	⬇️
pkg/container/docker_volume.go	0.00% <ø> (ø)
pkg/container/file_collector.go	37.30% <0.00%> (ø)
pkg/container/host_environment.go	0.00% <0.00%> (ø)
...ontainer/linux_container_environment_extensions.go	23.07% <0.00%> (-1.25%)	⬇️
pkg/exprparser/functions.go	66.32% <0.00%> (-1.04%)	⬇️
... and 25 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[KnisterPeter]

Looks good. Thanks for your contribution.