go mod: declare module version v2

Our git version is v2+ for some time now, but go.mod
still declared v1. Hopefully making both match makes
https://pkg.go.dev/github.com/rfjakob/gocryptfs/v2 work.

All the import paths have been fixed like this:

  find . -name \*.go | xargs sed -i s%github.com/rfjakob/gocryptfs/%github.com/rfjakob/gocryptfs/v2/%

1 files changed, 1 insertions, 1 deletions

diff --git a/help.go b/help.go
index d462b04..2a79e22 100644
--- a/help.go
+++ b/help.go
@@ -3,7 +3,7 @@ package main
 import (
 	"fmt"
 
-	"github.com/rfjakob/gocryptfs/internal/tlog"
+	"github.com/rfjakob/gocryptfs/v2/internal/tlog"
 )
 
 const tUsage = "" +