feat: build image from alpine for arm/v6

Dockerfile.alpine

@@ -0,0 +1,17 @@
+FROM alpine:latest
+
+# See Rclone Dockerfile
+# https://github.com/rclone/rclone/blob/master/Dockerfile
+
+LABEL "repository"="https://github.com/ttionya/vaultwarden-backup" \
+  "homepage"="https://github.com/ttionya/vaultwarden-backup" \
+  "maintainer"="ttionya <git@ttionya.com>"
+
+COPY scripts/*.sh /app/
+
+RUN chmod +x /app/*.sh \
+  && apk add --no-cache bash ca-certificates curl sqlite p7zip heirloom-mailx tzdata unzip \
+  && curl https://rclone.org/install.sh | bash \
+  && apk del curl unzip
+
+ENTRYPOINT ["/app/entrypoint.sh"]