Dagger module Devcontainer

[ssmiller25]

To assist in the development of the Dagger module itself. This will allow for creating a consistent environment, as well as the use for more cloud-based development environment (Github Codespaces, DevPod, etc).

This pull request introduces several changes to improve the development environment and update dependencies. The most important changes include adding a Dockerfile for the development container, configuring the development container, setting up Dependabot for dependency updates, and updating the README.md file.

Development environment setup:

• .devcontainer/Dockerfile: Added a Dockerfile to set up the development container with Go and Dagger.
• .devcontainer/devcontainer.json: Configured the development container with Docker-in-Docker feature and a post-start command to set Git's safe directory.

Dependency updates:

• .github/dependabot.yml: Added Dependabot configuration to automate dependency updates for the development container.

Documentation update:

• README.md: Renamed from Readme.md and added a badge to open the project in GitHub Codespaces.

[ssmiller25]

@DMajreka @rytswd @milindchawre ☝️ Thoughts?

[milindchawre]

I will test and let you know.