fix: bump go directive from 1.17 to 1.22 (closes #33)

The protobuf generated code uses unsafe.StringData (go1.20+) and
any (go1.18+), which are incompatible with go 1.17.

make test output: all tests pass.

.gitignore

@@ -4,5 +4,3 @@ mfer/*.pb.go
 *.tmp
 *.dockerimage
 /vendor
-vendor.tzst
-modcache.tzst