Have appveyor build relevant versions of Python. (celery#5887)

* Have appveyor build relevant and buildable versions of Python.

* Appveyor is missing CI requirements to build.

* Pin pycurl to version that will build with appveyor (because wheels files exist)

* Restrict python 2.7 64 bit version of python-dateutil for parse.

Author: matteius

appveyor.yml

@@ -12,21 +12,28 @@ environment:
     # a later point release.
     # See: https://www.appveyor.com/docs/installed-software#python
 
-    - PYTHON: "C:\\Python27"
-      PYTHON_VERSION: "2.7.x"
-      PYTHON_ARCH: "32"
-
-    - PYTHON: "C:\\Python34"
-      PYTHON_VERSION: "3.4.x"
-      PYTHON_ARCH: "32"
-
     - PYTHON: "C:\\Python27-x64"
       PYTHON_VERSION: "2.7.x"
       PYTHON_ARCH: "64"
       WINDOWS_SDK_VERSION: "v7.0"
 
-    - PYTHON: "C:\\Python34-x64"
-      PYTHON_VERSION: "3.4.x"
+    - PYTHON: "C:\\Python35-x64"
+      PYTHON_VERSION: "3.5.x"
+      PYTHON_ARCH: "64"
+      WINDOWS_SDK_VERSION: "v7.1"
+
+    - PYTHON: "C:\\Python36-x64"
+      PYTHON_VERSION: "3.6.x"
+      PYTHON_ARCH: "64"
+      WINDOWS_SDK_VERSION: "v7.1"
+      
+    - PYTHON: "C:\\Python37-x64"
+      PYTHON_VERSION: "3.7.x"
+      PYTHON_ARCH: "64"
+      WINDOWS_SDK_VERSION: "v7.1"
+      
+    - PYTHON: "C:\\Python38-x64"
+      PYTHON_VERSION: "3.8.x"
       PYTHON_ARCH: "64"
       WINDOWS_SDK_VERSION: "v7.1"
 
@@ -39,6 +46,7 @@ install:
   - "%PYTHON%/python -m pip install -U pip setuptools"
   - "%PYTHON%/Scripts/pip.exe install -U eventlet"
   - "%PYTHON%/Scripts/pip.exe install -U -r requirements/extras/thread.txt"
+  - "%PYTHON%/Scripts/pip.exe install -U -r requirements/test-ci-default.txt"
 
 build: off
 

requirements/extras/sqs.txt

@@ -1,2 +1,2 @@
 boto3>=1.9.125
-pycurl
+pycurl==7.43.0.2  # Latest version with wheel built (for appveyor)

requirements/test-ci-default.txt

@@ -21,4 +21,4 @@
 -r extras/azureblockblob.txt
 
 # SQS dependencies other than boto
-pycurl
+pycurl==7.43.0.2  # Latest version with wheel built (for appveyor)

requirements/test.txt

@@ -1,6 +1,7 @@
 case>=1.3.1
 pytest>=4.6.0,<5.0.0
 boto3>=1.9.178
+python-dateutil<2.8.1,>=2.1; python_version < '3.0'
 moto==1.3.7
 pre-commit
 -r extras/yaml.txt