packer cannot build and run on m5 cpu with cgo

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#### Overview of the Issue

packer transitively depends on `go-m1cpu v0.1.5` in `go.mod`. this version does not support new apple m5 CPUs, and so compiling with `cgo` enabled causes null pointer errors.

https://github.com/shoenig/go-m1cpu/issues/25

this can be fixed by upgrading to `go-m1cpu v0.2.1+` which adds support for m5 processors.

A paragraph or two about the issue you're experiencing.

#### Reproduction Steps

Steps to reproduce this issue

1. Build packer v1.15.0 from source on an Apple M5 with `CGO_ENABLED=1`
2. execute the built `packer` binary
3. Observe SIGSEGV in `github.com/shoenig/go-m1cpu.init.0()`
4. Repeat with `CGO_ENABLED=0`
5. no segfault

### Packer version

`1.15.0`

### Simplified Packer Template

If the file is longer than a few dozen lines, please include the URL to the
[gist](https://gist.github.com/) of the log or use the [Github detailed
format](https://gist.github.com/ericclemmons/b146fe5da72ca1f706b2ef72a20ac39d)
instead of posting it directly in the issue.

### Operating system and Environment details

OS, Architecture, and any other information you can provide about the
environment.

Apple M5 Pro chip, MacOS Tahoe 26.4 (25E246)

### Log Fragments and crash.log files

Include appropriate log fragments. If the log is longer than a few dozen lines,
please include the URL to the [gist](https://gist.github.com/) of the log or
use the [Github detailed format](https://gist.github.com/ericclemmons/b146fe5da72ca1f706b2ef72a20ac39d) instead of posting it directly in the issue.

Set the env var `PACKER_LOG=1` for maximum log detail.