feat: support github actions secrets (#53)

Usage:

```typescript
new GithubCustomResource(stack, "ActionsSecret", {
  onCreate: {
    endpoint: "actions",
    method: "createOrUpdateRepoSecret",
    parameters: {
      owner: "pepperize",
      repo: "cdk-github",
      secret_name: "any-name",
      value: ActionsSecret.fromSecretsManager(secret, "any-field"),
    },
    outputPaths: [],
    physicalResourceId: custom_resources.PhysicalResourceId.of("any-id"),
  },
  authOptions: AuthOptions.appAuth(authSecret),
});
```

Fixes #7

.projenrc.ts

@@ -14,6 +14,8 @@ const project = new AwsCdkConstructLibrary({
     "construct",
     "custom-resource",
     "github",
+    "actions",
+    "secret",
     "provider",
     "repository",
     "teams",
@@ -38,8 +40,11 @@ const project = new AwsCdkConstructLibrary({
     "@octokit/types",
     "@pepperize/projen-awscdk-construct@latest",
     "@types/aws-lambda",
+    "@types/libsodium-wrappers",
     "aws-lambda",
     "aws-sdk",
+    "libsodium",
+    "libsodium-wrappers",
   ],
 
   versionrcOptions: {
@@ -69,6 +74,10 @@ const project = new AwsCdkConstructLibrary({
   gitignore: ["cdk.out"],
 });
 
+project.eslint?.allowDevDeps("src/custom-resource-provider/encrypt.ts");
+project.eslint?.allowDevDeps("src/custom-resource-provider/execute-github-api-call.ts");
+project.eslint?.allowDevDeps("src/custom-resource-provider/get-secret-value.ts");
+
 project.gitpod?.addCustomTask({
   name: "setup",
   init: "yarn install && npx projen build",