Bump version of alpine docker image to 3.14

Dockerfile

@@ -5,7 +5,7 @@
 
 ##########################  BUILD IMAGE  ##########################
 # Alpine build image to build Conduit's statically compiled binary
-FROM alpine:3.12 as builder
+FROM alpine:3.14 as builder
 
 # Specifies if the local project is build or if Conduit gets build
 # from the official git repository. Defaults to the git repo.
@@ -13,11 +13,6 @@ ARG LOCAL=false
 # Specifies which revision/commit is build. Defaults to HEAD
 ARG GIT_REF=origin/master
 
-# Add 'edge'-repository to get Rust 1.45
-RUN sed -i \
-	-e 's|v3\.12|edge|' \
-	/etc/apk/repositories
-
 # Install packages needed for building all crates
 RUN apk add --no-cache \
         cargo \
@@ -36,7 +31,7 @@ RUN if [[ $LOCAL == "true" ]]; then \
 ########################## RUNTIME IMAGE ##########################
 # Create new stage with a minimal image for the actual
 # runtime image/container
-FROM alpine:3.12
+FROM alpine:3.14
 
 ARG CREATED
 ARG VERSION
@@ -86,9 +81,6 @@ RUN apk add --no-cache \
         curl \
         libgcc
 
-# Create a volume for the database, to persist its contents
-VOLUME ["/srv/conduit/.local/share/conduit"]
-
 # Test if Conduit is still alive, uses the same endpoint as Element
 HEALTHCHECK --start-period=5s \
     CMD curl --fail -s "http://localhost:$(grep -m1 -o 'port\s=\s[0-9]*' conduit.toml | grep -m1 -o '[0-9]*')/_matrix/client/versions" || \