Docker: pin alpine to v3.22 to fix docker build

v3.23 build fails with:

```
build-docker   > #11 18.86 npm warn deprecated stable@0.1.8: Modern JS
already guarantees Array#sort() is a stable sort, so this library is
deprecated. See the compatibility table on MDN:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#browser_compatibility
build-docker   > #11 CANCELED
build-docker   > ------
build-docker   >  > [kalamar  4/11] RUN cpm install --test -g
Cpanel::JSON::XS File::ShareDir::Install EV IO::Socket::Socks &&     cpm
install --test -g
"https://github.com/Akron/Mojolicious-Plugin-Localize/archive/refs/tags/v0.22.tar.gz"
&&     cpm install --test -g
"https://github.com/KorAP/KorAP-XML-TEI/archive/refs/tags/v2.6.1.tar.gz"
&&     cpm install --test -g
"https://github.com/KorAP/KorAP-XML-Krill/archive/refs/tags/v0.64.tar.gz"
&&     cpm install --test -g
"https://github.com/KorAP/KorAP-XML-CoNLL-U/archive/refs/tags/v0.6.3.tar.gz":
build-docker   > 2.068 DONE install IO-Socket-Socks-0.74
build-docker   > 2.814 DONE install common-sense-3.75
build-docker   > 3.430 DONE install File-ShareDir-Install-0.14
build-docker   > 7.264 DONE install Cpanel-JSON-XS-4.40
build-docker   > 11.31 FAIL install EV-4.36
build-docker   > 11.34 FAIL install EV-4.36
build-docker   > 11.34 5 distributions installed
```

Change-Id: Id64f596b0321ba5ba56d38c36a6b0b95ca8acf33
diff --git a/Dockerfile b/Dockerfile
index 27a8210..42f1cf0 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -26,7 +26,7 @@
        dev/robots.txt
 
 # Use alpine linux AS base image
-FROM alpine:latest AS kalamar
+FROM alpine:3.22 AS kalamar
 
 RUN apk update && \
     apk add --no-cache git \