chore: upgrade golangci-lint to v1.42.0 and add cache

[appleboy]

Signed-off-by: Bo-Yi Wu appleboy.tw@gmail.com

[codecov-commenter]

Codecov Report

Merging #22 (6adbd3a) into master (ed1c282) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master       #22   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines           19        26    +7     
=========================================
+ Hits            19        26    +7     

Flag	Coverage Δ
go-1.13	100.00% <ø> (?)
go-1.14	100.00% <ø> (?)
go-1.15	100.00% <ø> (?)
go-1.16	100.00% <ø> (?)
go-1.17	100.00% <ø> (?)
macos-latest	100.00% <ø> (?)
ubuntu-latest	100.00% <ø> (?)

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

Impacted Files	Coverage Δ
pprof.go	100.00% <0.00%> (ø)

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