Rebuild for pypy37

.ci_support/migrations/pypy37.yaml

@@ -0,0 +1,30 @@
+migrator_ts: 1608144114
+__migrator:
+    migration_number: 1
+    operation: key_add
+    primary_key: python
+    ordering:
+        python:
+            - 3.6.* *_cpython
+            - 3.7.* *_cpython
+            - 3.8.* *_cpython
+            - 3.9.* *_cpython
+            - 3.6.* *_73_pypy
+            - 3.7.* *_73_pypy  # new entry
+    paused: False
+    longterm: True
+    pr_limit: 8
+    bump_number: 0
+    exclude:
+      # this shouldn't attempt to modify the python feedstocks
+      - python
+      - pypy3.6
+      - pypy-meta
+
+python:                # [not (win or arm64)]
+  - 3.7.* *_73_pypy    # [not (win or arm64)]
+# additional entries to add for zip_keys
+numpy:                 # [not (win or arm64)]
+  - 1.19               # [not (win or arm64)]
+python_impl:           # [not (win or arm64)]
+  - pypy               # [not (win or arm64)]