remove references to outdated dependencies from preview dockerfiles (#536)

Author: anamnavi

Diff for: release/preview/arm32v7/docker/Dockerfile

@@ -1,4 +1,4 @@
-# Copyright (c) Microsoft Corporation. 
+# Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
 FROM arm32v7/ubuntu:bionic AS installer-env
@@ -58,7 +58,7 @@ COPY --from=installer-env ["/opt/microsoft/powershell", "/opt/microsoft/powershe
 
 RUN \
   apt-get update \
-  && apt-get install --no-install-recommends ca-certificates libunwind8 libssl1.0 libicu60 less --yes
+  && apt-get install --no-install-recommends ca-certificates libssl1.0 libicu60 less --yes
 
     # Give all user execute permissions and remove write permissions for others
 RUN chmod a+x,o-w ${PS_INSTALL_FOLDER}/pwsh \

Diff for: release/preview/debian10/docker/Dockerfile

@@ -60,7 +60,6 @@ RUN apt-get update \
         libc6 \
         libgcc1 \
         libgssapi-krb5-2 \
-        liblttng-ust0 \
         libstdc++6 \
         zlib1g \
     # PowerShell remoting over SSH dependencies

Diff for: release/preview/debian11/docker/Dockerfile

@@ -59,7 +59,6 @@ RUN apt-get update \
         libc6 \
         libgcc1 \
         libgssapi-krb5-2 \
-        liblttng-ust0 \
         libstdc++6 \
         zlib1g \
     # PowerShell remoting over SSH dependencies

Diff for: release/preview/ubuntu20.04/docker/Dockerfile

@@ -60,7 +60,6 @@ RUN apt-get update \
         libc6 \
         libgcc1 \
         libgssapi-krb5-2 \
-        liblttng-ust0 \
         libstdc++6 \
         zlib1g \
     # PowerShell remoting over SSH dependencies