Upgrade golangci-lint to v1.50.1

[tnasu]

Description

We're using the old one of golangci-lint-v1.42.1 and the latest one of golangci-lint-action-v3.3.1. And depandabot can upgrade golangci-lint-action only, which means that we have to upgrade golangci-lint manually. I fixed it with the latest tendermint's lint.yml. Of course, the existing code was affected, so I also fixed that.

• https://github.com/tendermint/tendermint/blob/83b7f4ad5bc77a56fdb51ec39ae13c1204dde6e0/.github/workflows/lint.yml

In addition, .golangci.yml is used for make lint only, so I removed it.

[codecov]

Codecov Report

Merging #505 (284f47c) into main (2828a22) will increase coverage by 0.09%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #505      +/-   ##
==========================================
+ Coverage   65.39%   65.49%   +0.09%     
==========================================
  Files         278      278              
  Lines       37972    37995      +23     
==========================================
+ Hits        24833    24885      +52     
+ Misses      11324    11300      -24     
+ Partials     1815     1810       -5     

Impacted Files	Coverage Δ
crypto/ed25519/ed25519.go	45.12% <0.00%> (-1.22%)	⬇️
abci/client/socket_client.go	72.09% <0.00%> (-0.88%)	⬇️
light/client.go	61.17% <0.00%> (-0.45%)	⬇️
blockchain/v0/pool.go	78.81% <0.00%> (-0.26%)	⬇️
proxy/multi_app_conn.go	47.66% <0.00%> (ø)
crypto/vrf/vrf_r2ishiguro.go
crypto/vrf/vrf_libsodium.go	78.57% <0.00%> (ø)
consensus/state.go	74.08% <0.00%> (+0.81%)	⬆️
consensus/msgs.go	85.10% <0.00%> (+0.91%)	⬆️
mempool/reactor.go	79.67% <0.00%> (+1.09%)	⬆️
... and 3 more