deps: using ethermint ac75a9a4a4a0 to support the 0.7.2 release

[hanchon]

Closes: #XXX

Description

---

For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

---

For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[fedekunze]

@hanchon build and unit tests are failing

[codecov]

Codecov Report

Merging #59 (d37f217) into main (58ed709) will increase coverage by 0.15%.
The diff coverage is 69.56%.

@@            Coverage Diff             @@
##             main      #59      +/-   ##
==========================================
+ Coverage   61.96%   62.11%   +0.15%     
==========================================
  Files           3        3              
  Lines         539      557      +18     
==========================================
+ Hits          334      346      +12     
- Misses        199      205       +6     
  Partials        6        6              

Impacted Files	Coverage Δ
app/test_helpers.go	0.00% <0.00%> (ø)
app/app.go	83.84% <100.00%> (+0.51%)	⬆️

[hanchon]

Forcing go version 1.17 on build workflow

      - uses: actions/setup-go@v2
        with:
          go-version: 1.17