manibuilder/alpine: Install libjaylink-dev when available

This should work since Alpine Linux v3.15.

Change-Id: I7143555b486697668c3456f7d57810023dc85ef2
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/137
diff --git a/util/manibuilder/Dockerfile.alpine b/util/manibuilder/Dockerfile.alpine
index 585275b..408dfc3 100644
--- a/util/manibuilder/Dockerfile.alpine
+++ b/util/manibuilder/Dockerfile.alpine
@@ -12,7 +12,7 @@
 		ln -sf /etc/ssl/cert.pem /etc/ssl/certs/ca-certificates.crt; \
 	fi
 
-RUN apk add libgpiod-dev meson || true
+RUN apk add libjaylink-dev libgpiod-dev meson || true
 
 # fix weird permissions in armhf-v3.11
 RUN [ -d /usr/share/git-core/templates ] && \