ci(build): remove artifact uf2 suffix
The archive now contains hex and uf2 files so the uf2 suffix is no longer accurate.  It probably should've been removed as part of the earlier hex commit.
See:
PR:
@@ -111,7 +111,7 @@ jobs:
- name: Archive build
uses: actions/upload-artifact@v2
with:
- name: "${{ steps.variables.outputs.artifact-name }}-uf2"
+ name: "${{ steps.variables.outputs.artifact-name }}"
path: |
build/zephyr/zmk.hex
build/zephyr/zmk.uf2
