go.toolchain: switch to tailscale.go1.21 (#8415)

Updates #8419

Signed-off-by: Jenny Zhang <[email protected]>

cmd/derper/depaware.txt

@@ -230,6 +230,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         io/fs                                                        from crypto/x509+
         io/ioutil                                                    from github.com/mitchellh/go-ps+
         log                                                          from expvar+
+        log/internal                                                 from log
         math                                                         from compress/flate+
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+

cmd/tailscale/depaware.txt

@@ -231,6 +231,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         io/fs                                                        from crypto/x509+
         io/ioutil                                                    from golang.org/x/sys/cpu+
         log                                                          from expvar+
+        log/internal                                                 from log
         math                                                         from compress/flate+
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+

cmd/tailscaled/depaware.txt

@@ -449,6 +449,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         io/fs                                                        from crypto/x509+
         io/ioutil                                                    from github.com/godbus/dbus/v5+
         log                                                          from expvar+
+        log/internal                                                 from log
   LD    log/syslog                                                   from tailscale.com/ssh/tailssh
         math                                                         from compress/flate+
         math/big                                                     from crypto/dsa+

go.toolchain.branch

@@ -1 +1 @@
-tailscale.go1.20
+tailscale.go1.21

go.toolchain.rev

@@ -1 +1 @@
-40dc4d834a5fde9872bcf470be50069f56c3e3b3
+492f6d9d792fa6e4caa388e4d7bab46b48d07ad5