chore: update to go 1.18

[coadler]

No description provided.

[codecov]

Codecov Report

Merging #628 (ce4039a) into main (eb18925) will decrease coverage by 0.23%.
The diff coverage is 91.66%.

@@            Coverage Diff             @@
##             main     #628      +/-   ##
==========================================
- Coverage   63.53%   63.29%   -0.24%     
==========================================
  Files         195      112      -83     
  Lines       11215    10432     -783     
  Branches       85        0      -85     
==========================================
- Hits         7125     6603     -522     
+ Misses       3334     3079     -255     
+ Partials      756      750       -6     

Flag	Coverage Δ
unittest-go-	62.42% <91.66%> (+0.25%)	⬆️
unittest-go-macos-latest	58.14% <66.66%> (-0.18%)	⬇️
unittest-go-ubuntu-latest	61.19% <66.66%> (+0.01%)	⬆️
unittest-go-windows-2022	57.35% <66.66%> (+0.22%)	⬆️
unittest-js	?

Impacted Files	Coverage Δ
codersdk/client.go	50.64% <ø> (-5.20%)	⬇️
cli/cliui/select.go	45.71% <66.66%> (+1.96%)	⬆️
coderd/database/pubsub.go	77.77% <100.00%> (+0.69%)	⬆️
coderd/provisionerjobs.go	61.92% <100.00%> (+1.92%)	⬆️
codersdk/workspacebuilds.go	58.33% <0.00%> (-8.34%)	⬇️
peerbroker/dial.go	75.43% <0.00%> (-7.02%)	⬇️
coderd/workspacebuilds.go	55.31% <0.00%> (-6.39%)	⬇️
provisionersdk/transport.go	74.46% <0.00%> (-6.39%)	⬇️
peer/conn.go	76.64% <0.00%> (-4.07%)	⬇️
... and 98 more

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[kylecarbs]

Just two minor nits. Hello generics!