cli: fix tsx entry points

Co-authored-by: Johan Haals <johan.haals@gmail.com>
Co-authored-by: Philipp Hugenroth <philipph@spotify.com>
Co-authored-by: Camila Belo <camilaibs@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/popular-clocks-whisper.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Fixed a bug where package exports entry points could not be `.tsx` files.

packages/cli/src/lib/builder/config.ts

@@ -157,7 +157,7 @@ export async function makeRollupConfigs(
         paths.resolveTargetRoot(
           'dist-types',
           relativePath(paths.targetRoot, targetDir),
-          e.path.replace(/\.ts$/, '.d.ts'),
+          e.path.replace(/\.(?:ts|tsx)$/, '.d.ts'),
         ),
       ]),
     );