Merge pull request #25472 from tklever/config-sources-env-option-update

feat: update ConfigSources options to match process.env typings

.changeset/neat-bears-divide.md

@@ -0,0 +1,5 @@
+---
+'@backstage/config-loader': patch
+---
+
+The `env` option of `ConfigSources.default` now correctly allows undefined members.

packages/config-loader/api-report.md

@@ -88,7 +88,7 @@ export interface ConfigSourcesDefaultOptions extends BaseConfigSourcesOptions {
   // (undocumented)
   argv?: string[];
   // (undocumented)
-  env?: Record<string, string>;
+  env?: Record<string, string | undefined>;
 }
 
 // @public

packages/config-loader/src/sources/ConfigSources.ts

@@ -107,7 +107,7 @@ export interface ConfigSourcesDefaultForTargetsOptions
  */
 export interface ConfigSourcesDefaultOptions extends BaseConfigSourcesOptions {
   argv?: string[];
-  env?: Record<string, string>;
+  env?: Record<string, string | undefined>;
 }
 
 /**