Fix broken links in docs/getting-started/introduction.mdx (#8155)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

docs/getting-started/introduction.mdx

@@ -100,7 +100,7 @@ The growth of the Gogs project wasn't possible without our world-class sponsors!
   <Card
     title="Installation"
     icon="download"
-    href="/installation"
+    href="/getting-started/installation"
   >
     Get your own Git service up and running in minutes.
   </Card>
@@ -121,7 +121,7 @@ The growth of the Gogs project wasn't possible without our world-class sponsors!
   <Card
     title="Upgrade"
     icon="arrow-up"
-    href="/upgrade"
+    href="/asking/release-strategy"
   >
     Keep up the version and energy.
   </Card>