Add Changelog for 1.7.3 (#6202) (#6207)

CHANGELOG.md

@@ -4,6 +4,20 @@ This changelog goes through all the changes that have been made in each release
 without substantial changes to our git log; to see the highlights of what has
 been added to each release, please refer to the [blog](https://blog.gitea.io).
 
+## [1.7.3](https://github.com/go-gitea/gitea/releases/tag/v1.7.3) - 2019-02-27
+* BUGFIXES
+  * Fix server 500 when trying to migrate to an already existing repository (#6188) (#6197)
+  * Load Issue attributes for API /repos/{owner}/{repo}/issues/{index} (#6122) (#6185)
+  * Fix bug whereby user could change private repository to public when force private enabled. (#6156) (#6165)
+  * Fix bug when update owner team then visit team's repo return 404 (#6119) (#6166)
+  * Fix heatmap and repository menu display in Internet Explorer 9+ (#6117) (#6137)
+  * Fix prohibit login check on authorization (#6106) (#6115)
+  * Fix LDAP protocol error regression by moving to ldap.v3 (#6105) (#6107)
+  * Fix deadlock in webhook PullRequest (#6102) (#6104)
+  * Fix redirect loop when password change is required and Gitea is installed as a suburl (#5965) (#6101)
+  * Fix compare button regression (#5929) (#6098)
+  * Recover panic in orgmode.Render if bad orgfile (#4982) (#5903) (#6097)
+
 ## [1.7.2](https://github.com/go-gitea/gitea/releases/tag/v1.7.2) - 2019-02-14
 * BUGFIXES
   * Remove all CommitStatus when a repo is deleted (#5940) (#5941)