feat: add MultiConfigChecker to validate multiple schemas in a single pass (#4045)

Towards #3821. We want to be able to validate other JSON config files. We can reimplement the PR file checking loop, but it's inefficient to fetch/scan the PR files multiple times. Instead, we implement a new `MultiConfigChecker` which does multiple schema checks in a single file fetch loop. It will create individual GitHub checks for each invalid config file.

feat: support validating JSON files as well
refactor: ConfigChecker uses MultiConfigChecker

Author: chingor13

packages/bot-config-utils/__snapshots__/bot-config-utils.js

@@ -7,7 +7,7 @@ exports[
   output: {
     title: 'Config schema error',
     summary: 'An error found in the config file',
-    text: 'You tried to add .github/test.yml, but the config file must be .github/test.yaml\n',
+    text: 'You tried to add .github/test.yml, but the config file must be .github/test.yaml',
   },
 };
 
@@ -33,7 +33,7 @@ exports[
   output: {
     title: 'Config schema error',
     summary: 'An error found in the config file',
-    text: 'You tried to add .github/test.yaml, but the config file must be .github/test.yml\n',
+    text: 'You tried to add .github/test.yaml, but the config file must be .github/test.yml',
   },
 };
 

packages/bot-config-utils/__snapshots__/multi-config-checker.js

@@ -0,0 +1,49 @@
+exports[
+  'MultiConfigChecker with config changes validates a single JSON config 1'
+] = {
+  name: 'foo config schema',
+  conclusion: 'failure',
+  head_sha: 'def234',
+  output: {
+    title: 'Config schema error',
+    summary: 'An error found in the config file',
+    text: '[\n    {\n        "instancePath": "",\n        "schemaPath": "#/additionalProperties",\n        "keyword": "additionalProperties",\n        "params": {\n            "additionalProperty": "test"\n        },\n        "message": "must NOT have additional properties"\n    }\n]',
+  },
+};
+
+exports[
+  'MultiConfigChecker with config changes validates a single YAML config 1'
+] = {
+  name: 'bar config schema',
+  conclusion: 'failure',
+  head_sha: 'def234',
+  output: {
+    title: 'Config schema error',
+    summary: 'An error found in the config file',
+    text: '[\n    {\n        "instancePath": "",\n        "schemaPath": "#/additionalProperties",\n        "keyword": "additionalProperties",\n        "params": {\n            "additionalProperty": "test"\n        },\n        "message": "must NOT have additional properties"\n    }\n]',
+  },
+};
+
+exports['MultiConfigChecker with config changes validates multiple configs 1'] =
+  {
+    name: 'foo config schema',
+    conclusion: 'failure',
+    head_sha: 'def234',
+    output: {
+      title: 'Config schema error',
+      summary: 'An error found in the config file',
+      text: '[\n    {\n        "instancePath": "",\n        "schemaPath": "#/additionalProperties",\n        "keyword": "additionalProperties",\n        "params": {\n            "additionalProperty": "test"\n        },\n        "message": "must NOT have additional properties"\n    }\n]',
+    },
+  };
+
+exports['MultiConfigChecker with config changes validates multiple configs 2'] =
+  {
+    name: 'bar config schema',
+    conclusion: 'failure',
+    head_sha: 'def234',
+    output: {
+      title: 'Config schema error',
+      summary: 'An error found in the config file',
+      text: '[\n    {\n        "instancePath": "",\n        "schemaPath": "#/additionalProperties",\n        "keyword": "additionalProperties",\n        "params": {\n            "additionalProperty": "test"\n        },\n        "message": "must NOT have additional properties"\n    }\n]',
+    },
+  };