Remove nanoserver:sac2016 (EOL)

See https://hub.docker.com/r/microsoft/nanoserver:

> The Windows Server 2016-based Nano Server container base image was a Semi-Annual Channel (SAC) release and received its final update on October 23rd, 2018.

Author: tianon

.appveyor.yml

@@ -5,20 +5,12 @@ environment:
   matrix:
     - version: 13
       variant: windowsservercore-ltsc2016
-    - version: 13
-      variant: nanoserver-sac2016
     - version: 12
       variant: windowsservercore-ltsc2016
-    - version: 12
-      variant: nanoserver-sac2016
     - version: 11
       variant: windowsservercore-ltsc2016
-    - version: 11
-      variant: nanoserver-sac2016
     - version: 8
       variant: windowsservercore-ltsc2016
-    - version: 8
-      variant: nanoserver-sac2016
 
 install:
   - ps: |

11/jdk/windows/nanoserver-sac2016/Dockerfile

@@ -138,7 +138,7 @@ for javaVersion in "${versions[@]}"; do
 		for v in \
 			oracle '' slim alpine \
 			windows/windowsservercore-{ltsc2016,1803,1809} \
-			windows/nanoserver-{sac2016,1803,1809} \
+			windows/nanoserver-{1803,1809} \
 		; do
 			dir="$javaVersion/$javaType${v:+/$v}"
 			[ -n "$v" ] && variant="$(basename "$v")" || variant=

12/jdk/windows/nanoserver-sac2016/Dockerfile

@@ -482,7 +482,7 @@ EOD
 			esac
 
 			for winVariant in \
-				nanoserver-{1809,1803,sac2016} \
+				nanoserver-{1809,1803} \
 				windowsservercore-{1809,1803,ltsc2016} \
 			; do
 				[ -f "$dir/windows/$winVariant/Dockerfile" ] || continue