fix: Support minimal mysql version 5.7.8. Fixes #2625

[whynowy]

Fixes: #2625

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234".
• I have written unit and/or e2e tests for my change. PRs without these are unlike to be merged.
• Optional. I've added My organization is added to the USERS.md.
• I've signed the CLA and required builds are green.

[codecov]

Codecov Report

Merging #2633 into master will increase coverage by 0.02%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #2633      +/-   ##
==========================================
+ Coverage   11.14%   11.16%   +0.02%     
==========================================
  Files          83       83              
  Lines       32652    32646       -6     
==========================================
+ Hits         3640     3646       +6     
+ Misses      28514    28502      -12     
  Partials      498      498              

Impacted Files	Coverage Δ
persist/sqldb/migrate.go	0.00% <0.00%> (ø)
pkg/apis/workflow/v1alpha1/workflow_types.go	10.93% <0.00%> (+0.02%)	⬆️
workflow/controller/dag.go	50.93% <0.00%> (+0.31%)	⬆️
workflow/controller/operator.go	61.30% <0.00%> (+0.31%)	⬆️
workflow/controller/steps.go	65.35% <0.00%> (+0.46%)	⬆️
workflow/templateresolution/context.go	69.46% <0.00%> (+4.28%)	⬆️

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[simster7]

Back-ported to 2.7