Improved markdown files: "1_Lab1.md" and "3_Lab3.md" by kakakakakku ยท Pull Request #20 ยท awslabs/aws-devops-essential

Hi, thank you for awesome hands-on ๐Ÿ‘ What I found that some markdown files include minor mistakes. So, I fixed it ๐Ÿ’ฏ 1_Lab1.md 3_Lab3.md License I agree it ๐Ÿ‘ By submitting this pull request, I co...