Revert accidental change of go version in go.mod (wasn't supposed to …

…commit).

Version set properly to 1.18, which is the new minimum needed for changes in this branch.
Run go mod tidy again with version set back to 1.18.

go.mod

@@ -1,8 +1,6 @@
 module github.com/shirou/gopsutil/v3
 
-go 1.21.0
-
-toolchain go1.22.3
+go 1.18
 
 require (
 	github.com/google/go-cmp v0.6.0

go.sum

@@ -14,7 +14,6 @@ github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c/go.mod h1:Om
 github.com/shoenig/go-m1cpu v0.1.6 h1:nxdKQNcEB6vzgA2E2bvzKIYRuNj7XNJ4S/aRSwKzFtM=
 github.com/shoenig/go-m1cpu v0.1.6/go.mod h1:1JJMcUBvfNwpq05QDQVAnx3gUHr9IYF7GNg9SUEw2VQ=
 github.com/shoenig/test v0.6.4 h1:kVTaSd7WLz5WZ2IaoM0RSzRsUD+m8wRR+5qvntpn4LU=
-github.com/shoenig/test v0.6.4/go.mod h1:byHiCGXqrVaflBLAMq/srcZIHynQPQgeyvkvXnjqq0k=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/tklauser/go-sysconf v0.3.12 h1:0QaGUFOdQaIVdPgfITYzaTegZvdCjmYO52cSFAEVmqU=