Update nightly merge workflow

[ericpre]

Following setting the default permissions for the hyperspy organization to "read contents" as mentioned in #2727 (comment), the nightly merge workflow fails as expected.

Progress of the PR

• Review action code and update robotology/gh-action-nightly-merge version
• Add write contents permission.
• Ready for review.

[codecov]

Codecov Report

Merging #2732 (74649fe) into RELEASE_next_minor (c799250) will not change coverage.
The diff coverage is n/a.

@@                 Coverage Diff                 @@
##           RELEASE_next_minor    #2732   +/-   ##
===================================================
  Coverage               77.69%   77.69%           
===================================================
  Files                     203      203           
  Lines                   30627    30627           
  Branches                 6670     6670           
===================================================
  Hits                    23796    23796           
  Misses                   5051     5051           
  Partials                 1780     1780           

Impacted Files	Coverage Δ
hyperspy/model.py	80.23% <0.00%> (ø)
hyperspy/component.py	85.42% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c799250...74649fe. Read the comment docs.