bump: blowfish/hugo version + change images extension

Dockerfile

@@ -1,5 +1,5 @@
 # Build Stage
-FROM hugomods/hugo:0.152.2 AS build
+FROM hugomods/hugo:0.154.5 AS build
 
 ARG BLOWFISH_VERSION
 
@@ -7,7 +7,7 @@ WORKDIR /opt/blog
 COPY . /opt/blog/
 
 RUN git submodule update --init --recursive && \
-    git -C themes/blowfish/ checkout v2.93.0
+    git -C themes/blowfish/ checkout v2.97.0
 RUN hugo
 
 # Publish Stage