Rename master -> main (#172)

Author: jorisvandenbossche

azure/posix.yml

@@ -13,7 +13,7 @@ jobs:
       PLAT: "x86_64"
       NP_BUILD_DEP: "numpy==1.17.3"
       CYTHON_BUILD_DEP: "cython==0.29.24"
-      NIGHTLY_BUILD_COMMIT: "master"
+      NIGHTLY_BUILD_COMMIT: "main"
       NIGHTLY_BUILD: "false"
       TEST_DEPENDS: "pytest pytest-xdist hypothesis"
       TEST_DIR: "tmp_for_test"

azure/windows.yml

@@ -11,7 +11,7 @@ jobs:
       BUILD_COMMIT: "v1.4.0rc0"
       NP_BUILD_DEP: "1.17.3"
       CYTHON_BUILD_DEP: "0.29.24"
-      NIGHTLY_BUILD_COMMIT: "master"
+      NIGHTLY_BUILD_COMMIT: "main"
       NIGHTLY_BUILD: "false"
       PYTHON_ARCH: "x64"
       TEST_DEPENDS: "pytest pytest-xdist hypothesis"