chore: add dependabot configuration

[lechnerc77]

Description

This PR adds a dependabot configuration for the ecosystems used in the project namelly:

• GitHub Actions
• Golang
• Devcontainer features (not base images)

The schedule is set to weekly (day is then Monday).

Type of change

• This pull request is a minor refactor, code cleanup, test improvement, or other maintenance task and doesn't change the functionality of Radius (issue link optional).

Additional Context

See discussion in Discord with @rynowak

[lechnerc77]

@rynowak as you mentioned in the chat in Discord, you can also enable the Dependabot alerts for security vulnerabilities located in the security tab of the repository, to get alerts for vulnerabilities in additon to the version updates triggered by the configuration made via this PR.

[rynowak]

Thanks for getting this started! /cc @sylvainsf @willdavsmith as FYI

[radius-functional-tests]

Radius functional test overview

🔍 Go to test action run

Name	Value
Repository	lechnerc77/radius
Commit ref	f6d11f3
Unique ID	a2e413957e
Image tag	pr-a2e413957e

Click here to see the list of tools in the current test run

• gotestsum 1.10.0
• KinD: v0.20.0
• Dapr: 1.12.0
• Azure KeyVault CSI driver: 1.4.2
• Azure Workload identity webhook: 1.1.0
• Bicep recipe location ghcr.io/radius-project/dev/test/functional/shared/recipes/<name>:pr-a2e413957e
• Terraform recipe location http://tf-module-server.radius-test-tf-module-server.svc.cluster.local/<name>.zip (in cluster)
• applications-rp test image location: ghcr.io/radius-project/dev/applications-rp:pr-a2e413957e
• controller test image location: ghcr.io/radius-project/dev/controller:pr-a2e413957e
• ucp test image location: ghcr.io/radius-project/dev/ucpd:pr-a2e413957e
• deployment-engine test image location: ghcr.io/radius-project/deployment-engine:latest

Test Status

⌛ Building Radius and pushing container images for functional tests...
✅ Container images build succeeded
⌛ Publishing Bicep Recipes for functional tests...
✅ Recipe publishing succeeded
⌛ Starting daprrp functional tests...
⌛ Starting ucp functional tests...
⌛ Starting shared functional tests...
⌛ Starting msgrp functional tests...
⌛ Starting kubernetes functional tests...
⌛ Starting samples functional tests...
⌛ Starting cli functional tests...
⌛ Starting datastoresrp functional tests...
✅ ucp functional tests succeeded
✅ msgrp functional tests succeeded
✅ samples functional tests succeeded
✅ kubernetes functional tests succeeded
✅ daprrp functional tests succeeded
✅ cli functional tests succeeded
✅ datastoresrp functional tests succeeded
✅ shared functional tests succeeded

[lechnerc77]

I also filed a PR in the Dashboard repository, to include dependabot there. Here is the PR for reference: radius-project/dashboard#58