build: adds a .envrc.local file for local development for dotenv (#538)

**What problem does this PR solve?**:

allows developers to have `.envrc.local` files to contain secret
information like `NUTANIX_USER` and `NUTANIX_PASSWORD`
based on this
direnv/direnv#544 (comment)

**Which issue(s) this PR fixes**:
Fixes #

**How Has This Been Tested?**:
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Author: faiq

.envrc

@@ -7,5 +7,7 @@ export DEVBOX_NO_ENVRC_UPDATE=1
 
 eval "$(devbox generate direnv --print-envrc --env-file .dev-envrc)"
 
+dotenv_if_exists '.envrc.local'
+
 # check out https://www.jetpack.io/devbox/docs/ide_configuration/direnv/
 # for more details

.gitignore

@@ -26,6 +26,7 @@ dist/
 
 *.tar.gz
 *.tar
+.envrc.local
 capd-kubeconfig
 
 ct_previous_*/