all: bump go.mod version and drop compatibility shims

Also, remove the legacy import annotations.

Fixes golang/go#68147

Change-Id: Ibfcc9322f27224c0ba92ea42cd56912a7d8783fd
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/594256
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>

openpgp/armor/armor.go

@@ -10,14 +10,15 @@
 // for their specific task. If you are required to interoperate with OpenPGP
 // systems and need a maintained package, consider a community fork.
 // See https://golang.org/issue/44226.
-package armor // import "golang.org/x/crypto/openpgp/armor"
+package armor
 
 import (
 	"bufio"
 	"bytes"
 	"encoding/base64"
-	"golang.org/x/crypto/openpgp/errors"
 	"io"
+
+	"golang.org/x/crypto/openpgp/errors"
 )
 
 // A Block represents an OpenPGP armored structure.

openpgp/clearsign/clearsign.go

@@ -13,7 +13,7 @@
 // for their specific task. If you are required to interoperate with OpenPGP
 // systems and need a maintained package, consider a community fork.
 // See https://golang.org/issue/44226.
-package clearsign // import "golang.org/x/crypto/openpgp/clearsign"
+package clearsign
 
 import (
 	"bufio"

openpgp/elgamal/elgamal.go

@@ -16,7 +16,7 @@
 // https://golang.org/issue/44226), and ElGamal in the OpenPGP ecosystem has
 // compatibility and security issues (see https://eprint.iacr.org/2021/923).
 // Moreover, this package doesn't protect against side-channel attacks.
-package elgamal // import "golang.org/x/crypto/openpgp/elgamal"
+package elgamal
 
 import (
 	"crypto/rand"

openpgp/errors/errors.go

@@ -9,7 +9,7 @@
 // for their specific task. If you are required to interoperate with OpenPGP
 // systems and need a maintained package, consider a community fork.
 // See https://golang.org/issue/44226.
-package errors // import "golang.org/x/crypto/openpgp/errors"
+package errors
 
 import (
 	"strconv"

openpgp/packet/packet.go

@@ -10,7 +10,7 @@
 // for their specific task. If you are required to interoperate with OpenPGP
 // systems and need a maintained package, consider a community fork.
 // See https://golang.org/issue/44226.
-package packet // import "golang.org/x/crypto/openpgp/packet"
+package packet
 
 import (
 	"bufio"

openpgp/read.go

@@ -9,7 +9,7 @@
 // for their specific task. If you are required to interoperate with OpenPGP
 // systems and need a maintained package, consider a community fork.
 // See https://golang.org/issue/44226.
-package openpgp // import "golang.org/x/crypto/openpgp"
+package openpgp
 
 import (
 	"crypto"

openpgp/s2k/s2k.go

@@ -10,7 +10,7 @@
 // for their specific task. If you are required to interoperate with OpenPGP
 // systems and need a maintained package, consider a community fork.
 // See https://golang.org/issue/44226.
-package s2k // import "golang.org/x/crypto/openpgp/s2k"
+package s2k
 
 import (
 	"crypto"