Add containerd's normalized architectures to archMapper

[MatthewCash]

While Docker gets its architecture property from utsname.machine, Podman uses containerd's normalizeArch function which returns an architecture not in act's archMapper map, leading to the architecture to be passed through to the runner. This causes some runners to fail if they expect the architecture to only be in GitHub's format.

I added the two missing entries from normalizearch, amd64 and arm64, to archMapper.

[codecov]

Codecov Report

Attention: 1028 lines in your changes are missing coverage. Please review.

Comparison is base (4989f44) 61.22% compared to head (c457c40) 60.86%.
Report is 305 commits behind head on master.

Files	Patch %	Lines
pkg/artifactcache/handler.go	65.32%	103 Missing and 43 partials ⚠️
pkg/runner/run_context.go	73.37%	75 Missing and 19 partials ⚠️
pkg/runner/expression.go	55.17%	66 Missing and 12 partials ⚠️
pkg/container/docker_run.go	1.47%	66 Missing and 1 partial ⚠️
pkg/runner/action_cache.go	50.74%	49 Missing and 17 partials ⚠️
pkg/container/docker_network.go	0.00%	56 Missing ⚠️
pkg/model/planner.go	28.57%	53 Missing and 2 partials ⚠️
pkg/model/workflow.go	52.72%	42 Missing and 10 partials ⚠️
pkg/runner/reusable_workflow.go	52.47%	42 Missing and 6 partials ⚠️
pkg/common/outbound_ip.go	0.00%	44 Missing ⚠️
... and 27 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2168      +/-   ##
==========================================
- Coverage   61.22%   60.86%   -0.36%     
==========================================
  Files          46       53       +7     
  Lines        7141     8990    +1849     
==========================================
+ Hits         4372     5472    +1100     
- Misses       2462     3076     +614     
- Partials      307      442     +135     

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