Update english branch to v1.8.1

[hughpearse]

Updates english language branch from 1.4.0-SNAPSHOT to 1.8.1

foo@bar:~$ git clone https://github.com/alibaba/Sentinel.git
foo@bar:~$ cd Sentinel/sentinel-dashboard
foo@bar:~$ git checkout dashboard/en
foo@bar:~$ mvn clean package -DskipTests
foo@bar:~$ java -Dserver.port=8081 -Dcsp.sentinel.dashboard.server=localhost:8081 -Dproject.name=sentinel-dashboard -Dauth.enabled=false -jar target/sentinel-dashboard.jar
foo@bar:~$ open http://127.0.0.1:8081

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7 out of 18 committers have signed the CLA.

:white_check_mark: brotherlu-xcq
:white_check_mark: Anilople
:white_check_mark: sczyh30
:white_check_mark: drgnchan
:white_check_mark: cdfive
:white_check_mark: Roger3581321
:white_check_mark: jnan806
:x: huakai-zhang
:x: VegetaPn
:x: quaff
:x: liqiangz
:x: gvma
:x: zhangyunan1994
:x: goodjava
:x: SparkLee
:x: hughpearse
:x: JerryChin
:x: FAnett1997

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[hughpearse]

I have signed the CLA, and my username is displayed in the list with a green tick ✅ hughpearse Ready to merge.