Bump version to v0.7.4

Author: m3nu

src/vorta/_version.py

@@ -1 +1 @@
-__version__ = '0.7.3'
+__version__ = '0.7.4'

src/vorta/assets/metadata/com.borgbase.Vorta.appdata.xml

@@ -40,7 +40,7 @@
     </screenshot>
   </screenshots>
   <releases>
-    <release version="v0.7.3" date="2021-02-18">
+    <release version="v0.7.4" date="2021-02-26">
     </release>
   </releases>
   <url type="bugtracker">https://github.com/borgbase/vorta/issues</url>