Adding Miniconda3 v4.8.2 (#1788)

* Adding Miniconda3.

* fix typo.

* only keep x64 installer.

manifests/Anaconda/Miniconda3/4.8.2.yaml

@@ -0,0 +1,20 @@
+Id: Anaconda.Miniconda3
+Name: Miniconda3
+AppMoniker: Miniconda3
+Version: 4.8.2
+Publisher: Anaconda
+Author: Anaconda
+License: BSD 3-Clause License
+LicenseUrl: https://docs.conda.io/en/latest/license.html
+Homepage: https://docs.conda.io/en/latest/miniconda.html
+Description: Miniconda is a free minimal installer for conda.
+Tags: "python"
+InstallerType: exe
+Switches:
+  Custom: /InstallationType=JustMe /AddToPath=0 /RegisterPython=0
+  Silent: /S
+  SilentWithProgress: /S
+Installers: 
+  - Arch: x64 
+    Url: https://repo.anaconda.com/miniconda/Miniconda3-py37_4.8.2-Windows-x86_64.exe
+    Sha256: 1701955cd637d1dad5a84958fd470649b79de973d1570541eb52857664b5056c