docs: Add learning resources in various pages (#114)

Author: brikis98

docs/bash-scripting/learning-resources.md

@@ -8,4 +8,5 @@ slug: "/bash/resources"
 ---
 
 - [You need to learn Bash Scripting right now playlist - NetworkChuck (Video)](https://youtube.com/playlist?list=PLIhvC56v63IKioClkSNDjW7iz-6TFvLwS)
-- [Devhints Bash Cheat Sheet](https://devhints.io/bash)
+- [Devhints Bash Cheat Sheet](https://devhints.io/bash)
+- [Google Shell Style Guide](https://google.github.io/styleguide/shellguide.html)

docs/gitops/learning-resources.md

@@ -9,3 +9,4 @@ slug: "/gitops/resources"
 
 - [What is GitOps - TechWorld with Nana](https://youtu.be/f5EpcWp0THw)
 - [ArgoCD Guide: Full Tutorial for Beginers](https://youtu.be/JLrR9RV9AFA)
+- [OpenGitOps](https://opengitops.dev/)

docs/kubernetes/learning-resources.md

@@ -13,3 +13,4 @@ slug: "/kubernetes/resources"
 - [BretFisher/udemy-docker-mastery GitHub repo](https://github.com/BretFisher/udemy-docker-mastery)
 - [Kubernetes official docs](https://kubernetes.io/docs/home/)
 - [Kubernetes Basic Concepts - Blog](https://spacelift.io/blog/kubernetes-tutorial)
+- [Kubernetes in Action](https://www.manning.com/books/kubernetes-in-action)

docs/terraform/learning-resources.md

@@ -8,4 +8,5 @@ slug: "/terraform/resources"
 ---
 
 - [Official Terraform Documentation](https://www.terraform.io/docs)
-- [Terraform Providers](https://registry.terraform.io/browse/providers)
+- [Terraform Providers](https://registry.terraform.io/browse/providers)
+- [Terraform: Up & Running](https://www.terraformupandrunning.com/)