go.mod: set toolchain to go1.24.0 & update github actions

[xnox]

Locally and in ci this will preffer, but not require, 1.24. As
currently we preffer to pick up 1.24 features (i.e. PQC TLS), but do
not explicitely require it.

Regularly bump the toolchain stanza to new upstream releases.

Whenever a toolchain feature becomes required do bump go stanza.

Confirmation that new workflow works correctly can be seen at:

• https://github.com/xnox/wolfictl/actions/runs/13380270071/job/37367480931

This is alternative to:

• go-1.24: move to go 1.24 #1447

Related:

• More specific handling/detection of Go toolchain versions actions/setup-go#457

[xnox]

and this will all explode upon next syft upgrade that bumps to 1.24 see anchore/syft#3660