Fix: Consumer panic when restart provider 

Fix: go get fail

Rft:Add history release to README.md

Ftr: for dubbo-go 1.5.2

Address notification batch mode
# Conflicts:
#	registry/directory/directory.go

Add: dubbogo docs

feat: update the comment of getty/listener

Rft: network & codec

Fmt: code clean

# Conflicts:
#	go.mod
#	go.sum

Ftr: consul service discovery

Ftr: add sentinel-golang  flow control/circuit breaker
# Conflicts:
#	go.sum

CI: Enhance DingTalk reminder information.

Ftr: File system service discovery

Ftr: Migrate travis Ci to GithubActions

Fix: add etcdv3 lease to defeat provider register info left in the registry when provider app  panic

ProxyInvoker cannot be extended

Fix: rename SethealthChecker to SetHealthChecker

Imp: Improve map access concurrency

* support attachment from map[sting]string to map[string]interface{} in invocation and result
# Conflicts:
#	cluster/router/tag/tag_router.go

Fix: #734

fix exporter append

Mod: Remove unnecessary return and judgement.
# Conflicts:
#	cluster/router/tag/tag_router.go

Fix: fix init config problem in HystrixFilter

Rft: Change file name to the same as interface name

Doc: modify changes.md