Problem: testnet binaries are not released together

[yihuang]

Solution:

• release testnet binaries together to make mantainence easier.
• sync hotfix release changelogs.
• add upgrade handler v4.2.7-testnet for testnet to sync with mainnet version.

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

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[bot]]

Codecov Report

Merging #988 (71f3fa7) into master (41a1076) will increase coverage by 3.01%. The diff coverage is 5.20%.

@@            Coverage Diff             @@
##           master     #988      +/-   ##
==========================================
+ Coverage   29.91%   32.92%   +3.01%     
==========================================
  Files         124      126       +2     
  Lines       19976    19988      +12     
==========================================
+ Hits         5975     6582     +607     
+ Misses      12962    12351     -611     
- Partials     1039     1055      +16     

Flag	Coverage Δ
integration_tests	20.54% <5.20%> (+<0.01%)	:arrow_up:
integration_tests_byzantine	9.60% <5.20%> (+0.01%)	:arrow_up:
integration_tests_gov	9.83% <5.20%> (+0.01%)	:arrow_up:
integration_tests_grpc	9.81% <5.20%> (+0.01%)	:arrow_up:
integration_tests_ibc	24.74% <5.20%> (+<0.01%)	:arrow_up:
integration_tests_ledger	9.81% <5.20%> (+0.01%)	:arrow_up:
integration_tests_slow	9.81% <5.20%> (+0.01%)	:arrow_up:
integration_tests_solomachine	9.60% <5.20%> (+0.01%)	:arrow_up:
integration_tests_upgrade	9.81% <5.20%> (+0.01%)	:arrow_up:
unit_tests	10.97% <5.20%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
app/upgrades.go	4.21% <4.21%> (ø)
app/app.go	91.11% <100.00%> (+12.71%)	:arrow_up:

... and 24 files with indirect coverage changes