go.mod: require Go 1.18

Also, update depaware for Go 1.18's dependency tree.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

cmd/tailscale/depaware.txt

@@ -100,7 +100,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/crypto/hkdf                                     from crypto/tls
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/poly1305                                 from golang.org/x/crypto/chacha20poly1305
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
    L    golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
@@ -186,6 +185,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         net/http/cgi                                                 from tailscale.com/cmd/tailscale/cli
         net/http/httptrace                                           from github.com/tcnksm/go-httpstat+
         net/http/internal                                            from net/http
+        net/netip                                                    from net
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
         os                                                           from crypto/rand+

cmd/tailscaled/depaware.txt

@@ -290,7 +290,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/crypto/hkdf                                     from crypto/tls+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/poly1305                                 from golang.org/x/crypto/chacha20poly1305+
+        golang.org/x/crypto/poly1305                                 from golang.zx2c4.com/wireguard/device
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
   LD    golang.org/x/crypto/ssh                                      from github.com/tailscale/ssh+
         golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
@@ -382,6 +382,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         net/http/httputil                                            from tailscale.com/cmd/tailscaled+
         net/http/internal                                            from net/http+
         net/http/pprof                                               from tailscale.com/cmd/tailscaled+
+        net/netip                                                    from net
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
         os                                                           from crypto/rand+

go.mod

@@ -1,6 +1,6 @@
 module tailscale.com
 
-go 1.17
+go 1.18
 
 require (
 	filippo.io/mkcert v1.4.3