!255 add gatekeeper mail list.

Merge pull request !255 from ZhengyuhangHans/master20200812

content/en/maillist/gatekeeper.md

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+listname = "Gatekeeper"
+emailaddress = "gatekeeper@openeuler.org"
+description = "Mail list for the discussions of the development of openEuler gate control."
+websitelink = "https://mailweb.openeuler.org/postorius/lists/gatekeeper@openeuler.org/"
+archivelink = "https://mailweb.openeuler.org/hyperkitty/list/gatekeeper@openeuler.org/"
+weight =  17
++++

content/zh/maillist/gatekeeper.md

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+listname = "Gatekeeper"
+emailaddress = "gatekeeper@openeuler.org"
+description = "openEuler社区CI门禁项目邮件列表。"
+websitelink = "https://mailweb.openeuler.org/postorius/lists/gatekeeper@openeuler.org/"
+archivelink = "https://mailweb.openeuler.org/hyperkitty/list/gatekeeper@openeuler.org/"
+weight =  17
++++