Add bug issue template

.github/ISSUE_TEMPLATE/incorrect-sass-output.md

@@ -0,0 +1,29 @@
+---
+name: Incorrect SASS Output
+about: There exists a differential between the output of grass and dart-sass
+title: ''
+labels: bug
+assignees: connorskees
+
+---
+
+**Minimal Reproducible Example**:
+```
+a {
+  color: red;
+}
+```
+
+**`grass` Output**:
+```
+a {
+  color: red;
+}
+```
+
+**`dart-sass` Output**:
+```
+a {
+  color: red;
+}
+```