chore: bump module version to v8 to follow semver convention

[thomas-nguy]

👮🏻👮🏻👮🏻 !!!! REFERENCE THE PROBLEM YOUR ARE SOLVING IN THE PR TITLE AND DESCRIBE YOUR SOLUTION HERE !!!! DO NOT FORGET !!!! 👮🏻👮🏻👮🏻

Next protocol upgrade will be v8

PR Checklist:

• Have you read the CONTRIBUTING.md?
• Does your PR follow the C4 patch requirements?
• Have you rebased your work on top of the latest master?
• Have you checked your code compiles? (make)
• Have you included tests for any non-trivial functionality?
• Have you checked your code passes the unit tests? (make test)
• Have you checked your code formatting is correct? (go fmt)
• Have you checked your basic code style is fine? (golangci-lint run)
• If you added any dependencies, have you checked they do not contain any known vulnerabilities? (go list -json -m all | nancy sleuth)
• If your changes affect the client infrastructure, have you run the integration test?
• If your changes affect public APIs, does your PR follow the C4 evolution of public contracts?
• If your code changes public APIs, have you incremented the crate version numbers and documented your changes in the CHANGELOG.md?
• If you are contributing for the first time, please read the agreement in CONTRIBUTING.md now and add a comment to this pull request stating that your PR is in accordance with the Developer's Certificate of Origin.

Thank you for your code, it's appreciated! :)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 33.82%. Comparing base (b1436a5) to head (9ecfb0d).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1205      +/-   ##
==========================================
+ Coverage   31.02%   33.82%   +2.80%     
==========================================
  Files         106      114       +8     
  Lines       18910    19208     +298     
==========================================
+ Hits         5867     6498     +631     
+ Misses      12000    11634     -366     
- Partials     1043     1076      +33     

Flag	Coverage Δ
integration_tests	24.16% <ø> (ø)
integration_tests_byzantine	11.12% <ø> (ø)
integration_tests_gov	11.34% <ø> (ø)
integration_tests_grpc	11.34% <ø> (ø)
integration_tests_ibc	24.94% <ø> (ø)
integration_tests_ledger	11.33% <ø> (ø)
integration_tests_slow	11.33% <ø> (ø)
integration_tests_solomachine	11.15% <ø> (ø)
integration_tests_upgrade	11.34% <ø> (ø)
unit_tests	12.51% <ø> (?)

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