MAINT: update environment file to include current and planned build requirements

Author: gregcaporaso

environment.yml

@@ -6,5 +6,7 @@ channels:
 dependencies:
   - qiime2-tiny
   - jupyter-book
+  - pip
   - pip:
-    - q2doc @ git+https://github.com/qiime2/sphinx-ext-qiime2.git@master
+    - q2doc @ git+https://github.com/qiime2/sphinx-ext-qiime2.git@master
+    - q2-dwq2 @ git+https://github.com/caporaso-lab/q2-dwq2.git@main