Readme: Fix failed RStudio installation on Ubuntu 21.10

Apparently not yet fixed upstream.

Thanks @Dorah H. !

Change-Id: I5ad9328784016323ccd61e81fc2a6be0dcdb062d
diff --git a/Readme.md b/Readme.md
index 5ad23dc..2e09bc4 100644
--- a/Readme.md
+++ b/Readme.md
@@ -107,6 +107,7 @@
 
 ```bash
 # Debian, Ubuntu, ...
+sudo apt -f install # install possibly missing RStudio dependencies
 sudo apt install r-base-dev libcurl4-gnutls-dev libxml2-dev libsodium-dev libsecret-1-dev libfontconfig1-dev libssl-dev
 
 # Fedora, CentOS, RHEL (for older versions use `yum` instead of `dnf`)