fix: Upgrade node to 20.11.1

This fixes an issue where running individual tests sometimes fails
with this error:

node:internal/assert:14 throw new ERR_INTERNAL_ASSERTION(message);

More info here: nodejs/node#48763
And here: nodejs/node#50383

.tool-versions

@@ -1,4 +1,4 @@
 elixir 1.15.7-otp-26
 erlang 26.1.2
-nodejs 20.7.0
+nodejs 20.11.1
 adr-tools 3.0.0