Update cheatsheets

tldr/linux/flatpak-run

@@ -0,0 +1,21 @@
+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# flatpak run
+
+> Run flatpak applications and runtimes.
+> More information: <https://docs.flatpak.org/en/latest/flatpak-command-reference.html#flatpak-run>.
+
+- Run an installed application:
+
+`flatpak run {{com.example.app}}`
+
+- Run an installed application from a specific branch e.g. stable, beta, master:
+
+`flatpak run --branch={{stable|beta|master|...}} {{com.example.app}}`
+
+- Run an interactive shell inside a flatpak:
+
+`flatpak run --command={{sh}} {{com.example.app}}`