ratelimit plugin don't work on go 1.19

[yingziwu]

OS: Linux 5.18.16-zen1-1-zen
Go version: go1.19 linux/amd64

---

step to reproduce:

go install github.com/caddyserver/xcaddy/cmd/xcaddy@latest
xcaddy build \
        --with github.com/RussellLuo/caddy-ext/ratelimit

./caddy

error log:

$ ./caddy  
panic: Something in this program imports go4.org/unsafe/assume-no-moving-gc to declare that it assumes a non-moving garbage collector, but your version of go4.org/unsafe/assume-no-moving-gc hasn't been updated to assert that it's safe against the go1.19 runtime. If you want to risk it, run with environment variable ASSUME_NO_MOVING_GC_UNSAFE_RISK_IT_WITH=go1.19 set. Notably, if go1.19 adds a moving garbage collector, this program is unsafe to use.

goroutine 1 [running]:
go4.org/unsafe/assume-no-moving-gc.init.0()
        go4.org/unsafe/assume-no-moving-gc@v0.0.0-20211027215541-db492cf91b37/untested.go:25 +0x1f4

[RussellLuo]

@yingziwu Thanks for the report! I'll fix this shortly.