chore: allow individuals to extend direnv config (#3847)

Author: ARR4N

.envrc

@@ -12,3 +12,6 @@ export AVALANCHEGO_PATH=$PWD/build/avalanchego
 # Configure the local plugin directory for both avalanchego and tmpnet usage
 mkdir -p $PWD/build/plugins                                       # avalanchego will FATAL if the directory does not exist
 export AVAGO_PLUGIN_DIR="${AVAGO_PLUGIN_DIR:-$PWD/build/plugins}" # Use an existing value if set
+
+# Allow individuals to add their own customisation
+source_env_if_exists .envrc.local

.gitignore

@@ -64,3 +64,5 @@ vendor
 **/testdata
 
 .direnv
+# Personal extension to .envrc
+.envrc.local