fix: install hype from main branch in Dockerfile

The @latest tag resolves to the last GitHub release which doesn't
include the first/after template functions yet. Use @main to install
from the latest commit.

Author: corylanou

Dockerfile

@@ -1,5 +1,5 @@
 FROM golang:1.25 AS builder
-RUN go install github.com/gopherguides/hype/cmd/hype@latest
+RUN go install github.com/gopherguides/hype/cmd/hype@main
 
 FROM golang:1.25
 COPY --from=builder /go/bin/hype /usr/local/bin/hype