Recommend building against caddy 2.7.6

Signed-off-by: Chris Rose <offline@offby1.net>

Author: offbyone

README.md

@@ -20,7 +20,7 @@ Use [xcaddy](https://github.com/caddyserver/xcaddy) to build Caddy with the
 Tailscale plugin included.
 
 ```
-xcaddy build v2.7.3 --with github.com/tailscale/caddy-tailscale
+xcaddy build v2.7.6 --with github.com/tailscale/caddy-tailscale
 ```
 
 ## Caddy network listener

go.mod

@@ -2,8 +2,6 @@ module github.com/tailscale/caddy-tailscale
 
 go 1.22.0
 
-toolchain go1.22.1
-
 require (
 	github.com/caddyserver/caddy/v2 v2.7.3
 	go.uber.org/zap v1.26.0