go.mod,go.sum: bump wireguard-go to fix AllowedIPs mem leak

Pulls in https://github.com/tailscale/wireguard-go/pull/85 which
fixes an unbounded memory leak in mkIPInCIDRsTestFunc. It used a
package-level placeholder Peer, and AllowedIPs.Insert threads every
trie node onto that peer's trieEntries list, so each call leaked
its whole trie. SetAllowedIPs calls it on every netmap update, so
peer churn accumulated trie nodes until the client OOMed.

Fixes tailscale/corp#47010

Signed-off-by: Adriano Sela Aviles <adriano@tailscale.com>