bump version and use py3

Dockerfile

@@ -1,11 +1,14 @@
 FROM library/alpine:3.5
 
-# deps - python openssl curl sed grep mktemp
-# boto 3 - AWS SDK for python
+# Credit: @frol for python3 - https://github.com/frol/docker-alpine-python3/blob/master/Dockerfile
+
+# deps - python3 openssl curl sed grep mktemp
+# boto3 - AWS SDK for python
 RUN apk add --no-cache --virtual .build-deps git \
-    && apk add --no-cache --virtual .dehydrated-rundeps python py2-pip bash openssl curl \
-    && pip install --upgrade pip \
-    && pip install dns-lexicon boto3 dns-lexicon[route53] dns-lexicon[transip] \
+    && apk add --no-cache --virtual .dehydrated-rundeps python3 bash openssl curl \
+    && pip3 install --upgrade pip boto3 dns-lexicon==1.2.1 dns-lexicon[route53]==1.2.1 dns-lexicon[transip]==1.2.1 \
+    && rm -r /root/.cache \
+
     && cd /tmp \
     && git clone https://github.com/lukas2511/dehydrated.git --depth 1 \
     && chmod a+x dehydrated/dehydrated \
@@ -14,6 +17,7 @@ RUN apk add --no-cache --virtual .build-deps git \
     && chmod a+x lexicon/examples/dehydrated.default.sh \
     && mv lexicon/examples/dehydrated.default.sh /usr/bin/dehydrated-dns \
     && rm -rf /tmp/* \
+
     && apk del .build-deps
 
 COPY config /etc/dehydrated/config