go.mod: update golang.org/x dependencies

Update golang.org/x dependencies to their latest tagged versions.

Change-Id: If9754f35f3d490909f6a93bbb2fc715510265749
Reviewed-on: https://go-review.googlesource.com/c/image/+/626376
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>

go.mod

@@ -2,4 +2,4 @@ module golang.org/x/image
 
 go 1.18
 
-require golang.org/x/text v0.19.0
+require golang.org/x/text v0.20.0

go.sum

@@ -1,2 +1,2 @@
-golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
-golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
+golang.org/x/text v0.20.0 h1:gK/Kv2otX8gz+wn7Rmb3vT96ZwuoxnQlY+HlJVj7Qug=
+golang.org/x/text v0.20.0/go.mod h1:D4IsuqiFMhST5bX19pQ9ikHC2GsaKyk/oF+pn3ducp4=