Update build.yml in preparation for 3.15 upgrade

README.md

@@ -14,7 +14,7 @@ APKBUILDs yourself, be aware that the version numbers here may be outdated.
 When a new Alpine version is released:
 
 1. Update the Alpine version in build.yml
-1. Update non-sr.ht packages to latest upstream version, or bump pkgrel
+1. Update non-sr.ht packages to latest upstream version, reset pkgrel to 0
 1. `./submit-build` everything _except_ for *.sr.ht
 1. Update pkgver in *.sr.ht packages, commit & push & run `./submit-build`
 1. Update build manifests upstream for *.sr.ht
@@ -23,7 +23,7 @@ When a new Alpine version is released:
 
 **Tips**
 
-- Bump all the freaking pkgrels or the upgrade won't go well
+- Upgrade systems with apk upgrade -a
 - Update the python version in the Makefiles
 - Update the python version with nginx
 - Let the *.sr.ht packages upgrade themselves

build.yml

@@ -1,7 +1,7 @@
-image: alpine/3.14
+image: alpine/3.15
 repositories:
   sr.ht: >
-    https://mirror.sr.ht/alpine/v3.14/sr.ht/
+    https://mirror.sr.ht/alpine/v3.15/sr.ht/
     https://mirror.sr.ht/alpine/alpine%40sr.ht.rsa.pub
     alpine@sr.ht.rsa.pub
 packages: