Bump up minimum numpy version in windows37 job (#34750)

Author: bharatr21

ci/azure/windows.yml

@@ -13,7 +13,7 @@ jobs:
         CONDA_PY: "36"
         PATTERN: "not slow and not network"
 
-      py37_np141:
+      py37_np18:
         ENV_FILE: ci/deps/azure-windows-37.yaml
         CONDA_PY: "37"
         PATTERN: "not slow and not network"

ci/deps/azure-windows-37.yaml

@@ -22,7 +22,7 @@ dependencies:
   - matplotlib=2.2.*
   - moto
   - numexpr
-  - numpy=1.14.*
+  - numpy=1.18.*
   - openpyxl
   - pyarrow=0.14
   - pytables