Update to Go 1.18 and replace fnv-1a with xxhash (#158)

* Update modules and go 1.18

* Use xxhash instead of fnv-1a

* Update go version in dockerfile and github workflow

pool/fixpool.go

@@ -1,7 +1,7 @@
 package pool
 
 import (
-	"github.com/segmentio/fasthash/fnv1a"
+	"github.com/cespare/xxhash/v2"
 )
 
 type WorkerPool struct {
@@ -29,7 +29,7 @@ func New(maxWorkers int) *WorkerPool {
 }
 
 func (p *WorkerPool) Submit(uid string, task func()) {
-	idx := fnv1a.HashString64(uid) % uint64(p.maxWorkers)
+	idx := xxhash.Sum64([]byte(uid)) % uint64(p.maxWorkers)
 	if task != nil {
 		p.taskQueue[idx] <- task
 	}