Rebuild Dockerfiles to match latest Dockerfile.j2 template

Picks up a couple of missed changes from b837348b and ccf6ee79.

docker/amd64/mysql/Dockerfile.alpine

@@ -19,7 +19,7 @@ FROM bitwardenrs/web-vault@sha256:feb3f46d15738191b9043be4cdb1be2c0078ed411e7b7b
 
 ########################## BUILD IMAGE  ##########################
 # Musl build image for statically compiled binary
-FROM clux/muslrust:nightly-2019-12-19 as build
+FROM clux/muslrust:nightly-2020-03-09 as build
 
 # set mysql backend
 ARG DB=mysql
@@ -31,6 +31,7 @@ ENV DEBIAN_FRONTEND=noninteractive LANG=C.UTF-8 TZ=UTC TERM=xterm-256color
 RUN rustup set profile minimal
 
 ENV USER "root"
+ENV RUSTFLAGS='-C link-arg=-s'
 
 # Install MySQL package
 RUN apt-get update && apt-get install -y \

docker/amd64/postgresql/Dockerfile.alpine

@@ -19,7 +19,7 @@ FROM bitwardenrs/web-vault@sha256:feb3f46d15738191b9043be4cdb1be2c0078ed411e7b7b
 
 ########################## BUILD IMAGE  ##########################
 # Musl build image for statically compiled binary
-FROM clux/muslrust:nightly-2019-12-19 as build
+FROM clux/muslrust:nightly-2020-03-09 as build
 
 # set postgresql backend
 ARG DB=postgresql
@@ -31,6 +31,7 @@ ENV DEBIAN_FRONTEND=noninteractive LANG=C.UTF-8 TZ=UTC TERM=xterm-256color
 RUN rustup set profile minimal
 
 ENV USER "root"
+ENV RUSTFLAGS='-C link-arg=-s'
 
 # Install PostgreSQL package
 RUN apt-get update && apt-get install -y \

docker/amd64/sqlite/Dockerfile.alpine

@@ -19,7 +19,7 @@ FROM bitwardenrs/web-vault@sha256:feb3f46d15738191b9043be4cdb1be2c0078ed411e7b7b
 
 ########################## BUILD IMAGE  ##########################
 # Musl build image for statically compiled binary
-FROM clux/muslrust:nightly-2019-12-19 as build
+FROM clux/muslrust:nightly-2020-03-09 as build
 
 # set sqlite as default for DB ARG for backward compatibility
 ARG DB=sqlite
@@ -31,6 +31,7 @@ ENV DEBIAN_FRONTEND=noninteractive LANG=C.UTF-8 TZ=UTC TERM=xterm-256color
 RUN rustup set profile minimal
 
 ENV USER "root"
+ENV RUSTFLAGS='-C link-arg=-s'
 
 # Creates a dummy project used to grab dependencies
 RUN USER=root cargo new --bin /app