PYTHON-2367 Add release automation for Python 3.9

.evergreen/build-mac.sh

@@ -18,7 +18,18 @@ for VERSION in 2.7 3.4 3.5 3.6 3.7 3.8; do
     fi
     rm -rf build
 
-    $PYTHON setup.py bdist_wheel
+    # Install wheel if not already there.
+    if ! $PYTHON -m wheel version; then
+        createvirtualenv $PYTHON releasevenv
+        WHEELPYTHON=python
+        pip install --upgrade wheel
+    else
+        WHEELPYTHON=$PYTHON
+    fi
+
+    $WHEELPYTHON setup.py bdist_wheel
+    deactivate || true
+    rm -rf releasevenv
 
     # Test that each wheel is installable.
     for release in dist/*; do

.evergreen/build-manylinux-internal.sh

@@ -11,8 +11,7 @@ mv dist/* validdist || true
 
 # Compile wheels
 for PYTHON in /opt/python/*/bin/python; do
-    # Skip Python 3.3 and 3.9.
-    if [[ "$PYTHON" == *"cp33"* || "$PYTHON" == *"cp39"* ]]; then
+    if [[ ! $PYTHON =~ (cp27|cp34|cp35|cp36|cp37|cp38|cp39) ]]; then
         continue
     fi
     # https://github.com/pypa/manylinux/issues/49

.evergreen/build-manylinux.sh

@@ -27,7 +27,8 @@ unexpected=$(find dist \! \( -iname dist -or \
                              -iname '*cp35*' -or \
                              -iname '*cp36*' -or \
                              -iname '*cp37*' -or \
-                             -iname '*cp38*' \))
+                             -iname '*cp38*' -or \
+                             -iname '*cp39*' \))
 if [ -n "$unexpected" ]; then
   echo "Unexpected files:" $unexpected
   exit 1

.evergreen/build-windows.sh

@@ -8,7 +8,7 @@ rm -rf validdist
 mkdir -p validdist
 mv dist/* validdist || true
 
-for VERSION in 27 34 35 36 37 38; do
+for VERSION in 27 34 35 36 37 38 39; do
     _pythons=(C:/Python/Python${VERSION}/python.exe \
               C:/Python/32/Python${VERSION}/python.exe)
     for PYTHON in "${_pythons[@]}"; do

.evergreen/config.yml

@@ -817,6 +817,7 @@ tasks:
 
     - name: "release"
       tags: ["release"]
+      exec_timeout_secs: 216000  # 60 minutes (manylinux task is slow).
       git_tag_only: true
       commands:
         - command: shell.exec