Add a simple GitHub issue template based on the one of PowerShell Core. (#865)

Author: bergmeister

.github/ISSUE_TEMPLATE.md.txt

@@ -0,0 +1,32 @@
+Steps to reproduce
+------------------
+
+```powershell
+
+```
+
+Expected behavior
+-----------------
+
+```none
+
+```
+
+Actual behavior
+---------------
+
+```none
+
+```
+
+Environment data
+----------------
+
+<!-- Provide the output of the following 2 commands -->
+
+```powershell
+> $PSVersionTable
+
+> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
+
+```