chore(.envrc): source the direnv flake-overrides plugin

Makes the blocksense-network direnv flake-overrides helper available so
flake inputs can be overridden from a local .env (see
https://direnv-flake-overrides.blocksense.network). Pinned to the current
stable plugin version.

Author: zah

.envrc

@@ -6,6 +6,11 @@ if ! has nix_direnv_version || ! nix_direnv_version 3.1.0; then
   source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.1.0/direnvrc" "sha256-yMJ2OVMzrFaDPn7q8nCBZFRYpL/f0RcHzhmw/i6btJM="
 fi
 
+# See https://direnv-flake-overrides.blocksense.network
+# Allows flake inputs to be easily overridden from your local .env file
+source_url "https://direnv-flake-overrides.blocksense.network/plugin" \
+  "sha256-BTxlsheP/7/FQw9IBPGFc6zYTl5S2qdAAt3EUqfkbjI="
+
 dotenv_if_exists
 
 mkdir -p "$PWD/.devenv"