chore: preserve 'pytype' artifacts during synth (#90)

* chore: use '.pytype' vs. 'pytype_output' for pytype cache

* chore: add snippet-bot to CI (via synth)

* chore: drop obsolete warning about editable installs

* chore: add secrets manager, docs-presubmit to CI (via synth)

* chore: manual synth

Closes: #66.
Closes: #56.

synth.py

diff --git a/synth.py b/synth.py
index 1e8abc9..2a525c8 100644
--- a/synth.py
+++ b/synth.py
@@ -25,4 +25,16 @@
 # Add templated files
 # ----------------------------------------------------------------------------
 templated_files = common.py_library(cov_level=100)
-s.move(templated_files, excludes=["noxfile.py", ".flake8", ".coveragerc", "setup.cfg"])
\ No newline at end of file
+s.move(templated_files, excludes=["noxfile.py", ".flake8", ".coveragerc", "setup.cfg"])
+
+# Add pytype support
+s.replace(
+    ".gitignore",
+    """\
+.pytest_cache
+""",
+    """\
+.pytest_cache
+.pytype
+""",
+)