standardize apt-get

Dockerfile

@@ -1,4 +1,4 @@
-FROM lsiobase/alpine:3.11 as buildstage
+FROM ghcr.io/linuxserver/baseimage-alpine:3.13 as buildstage
 
 ARG PS_VERSION
 

root/etc/cont-init.d/95-apt-get

@@ -0,0 +1,3 @@
+#!/usr/bin/with-contenv bash
+
+apt-get update

root/etc/cont-init.d/98-powershell

@@ -4,7 +4,6 @@ ARCH=$(uname -m)
 
 if [ -f "/powershell/powershell_${ARCH}.tar.gz" ]; then
     echo "Installing PowerShell"
-  apt-get update
     apt-get install -y \
         libicu60 \
         libunwind8