add yaml-static as depdency for alpine image

alpine/Dockerfile

@@ -53,7 +53,7 @@ RUN sh -ex bin/shards.sh && strip bin/shards
 # start from a clean image
 FROM alpine:$alpine_version
 # add dependencies commonly required for building crystal applications
-RUN apk add --update --no-cache musl-dev gcc pcre2-dev libevent-dev libevent-static openssl-dev openssl-libs-static libxml2-dev zlib-dev zlib-static git make yaml-dev libxml2-static gmp-dev xz-static
+RUN apk add --update --no-cache musl-dev gcc pcre2-dev libevent-dev libevent-static openssl-dev openssl-libs-static libxml2-dev zlib-dev zlib-static git make yaml-dev libxml2-static gmp-dev xz-static yaml-static
 # copy the binaries + stdlib + libgc from the build stage
 COPY --from=builder /usr/src/crystal/*.md /usr/share/doc/crystal/
 COPY --from=builder /usr/src/crystal/man/crystal.1.gz /usr/share/man/man1/