Merge pull request #8808 from backstage/rugvip/depr1

removed deprecations from the 2021-11-25 release

.changeset/lazy-gorillas-tell.md

@@ -0,0 +1,7 @@
+---
+'@backstage/core-plugin-api': minor
+---
+
+Removed previously deprecated exports: `PluginHooks`, `PluginOutput`, and `FeatureFlagOutput`.
+
+The deprecated `register` method of `PluginConfig` has been removed, as well as the deprecated `output` method of `BackstagePlugin`.

.changeset/rotten-files-wink.md

@@ -0,0 +1,5 @@
+---
+'@backstage/core-components': patch
+---
+
+Updated `ResponseErrorPanel` to not use the deprecated `data` property of `ResponseError`.

.changeset/silver-mice-bake.md

@@ -0,0 +1,5 @@
+---
+'@backstage/core-app-api': minor
+---
+
+Removed previously deprecated `ApiRegistry` export.

.changeset/violet-dingos-relate.md

@@ -0,0 +1,7 @@
+---
+'@backstage/errors': minor
+---
+
+Removed the deprecated exports `ErrorResponse` and `parseErrorResponse`.
+
+Removed the deprecated `constructor` and the deprecated `data` property of `ResponseError`.