fix typo

Dockerfile

@@ -12,7 +12,7 @@ RUN \
   apt-get install -y python && \
   apt-get install -y python-requests && \
   apt install -y gpg && \
-  ppt install -y apt-transport-https && \
+  apt install -y apt-transport-https && \
 t-get install -y wget && \
   apt-get install -y curl && \
   rm -rf /var/lib/apt/lists/* && \