chore: use headings in bug report templates (#1967)

* chore: use headings in bug report templates

* chore: use heading level 2 to add underline

.github/ISSUE_TEMPLATE/---bug-report.md

@@ -7,25 +7,29 @@ assignees: ''
 
 ---
 
-**Describe the bug**
+## Describe the bug
 A clear and concise description of what the bug is.
 
-**SDK version number**
+## Your environment
+#### SDK version number
+`@aws-sdk/package-name@version`
 
-**Is the issue in the browser/Node.js/ReactNative?**
+#### Is the issue in the browser/Node.js/ReactNative?
 Browser/Node.js/ReactNative
 
-**Details of the browser/Node.js/ReactNative version**
+#### Details of the browser/Node.js/ReactNative version
 Paste output of `npx envinfo --browsers` or `node -v` or `react-native -v`
 
-**To Reproduce (observed behavior)**
-Steps to reproduce the behavior (please share code or minimal repo)
+## Steps to reproduce
+Please share code or minimal repo, and steps to reproduce the behavior.
+#### Observed behavior
+A clear and concise description of what happens.
 
-**Expected behavior**
-A clear and concise description of what you expected to happen.
+#### Expected behavior
+A clear and concise description of what you were expecting to happen.
 
-**Screenshots**
+#### Screenshots
 If applicable, add screenshots to help explain your problem.
 
-**Additional context**
+## Additional context
 Add any other context about the problem here.

.github/ISSUE_TEMPLATE/---feature-request.md

@@ -7,14 +7,14 @@ assignees: ''
 
 ---
 
-**Is your feature request related to a problem? Please describe.**
+### Is your feature request related to a problem? Please describe.
 A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
 
-**Describe the solution you'd like**
+### Describe the solution you'd like
 A clear and concise description of what you want to happen.
 
-**Describe alternatives you've considered**
+### Describe alternatives you've considered
 A clear and concise description of any alternative solutions or features you've considered.
 
-**Additional context**
+### Additional context
 Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/--documentation.md

@@ -7,17 +7,19 @@ assignees: ''
 
 ---
 
-**Describe the issue with documentation**
+## Describe the issue with documentation
 A clear and concise description of what the issue is.
 
-**To Reproduce (observed behavior)**
-Steps to reproduce the behavior (please share code or minimal repo)
+## Steps to reproduce
+Please share code or minimal repo if required, and steps to reproduce the behavior.
+#### Observed behavior
+A clear and concise description of what happens.
 
-**Expected behavior**
-A clear and concise description of what you expected to happen.
+#### Expected behavior
+A clear and concise description of what you were expecting to happen.
 
-**Screenshots**
+#### Screenshots
 If applicable, add screenshots to help explain your problem.
 
-**Additional context**
+## Additional context
 Add any other context about the problem here.