Simplify job names

(cherry picked from commit 3792f658)

.gitlab-ci.yml

@@ -26,7 +26,7 @@ workflow:
     paths:
       - out/*
 
-build-linux:
+linux:
   extends: .build
   parallel:
     matrix:
@@ -59,7 +59,7 @@ build-linux:
     TARBALL_EXT: tar.xz
     ADD_CABAL_ARGS: "--enable-split-sections"
 
-build-linux-alpine:
+alpine-linux:
   extends: .build
   parallel:
     matrix:
@@ -123,7 +123,7 @@ build-aarch64-darwin:
     paths:
       - .brew
 
-build-x86_64-windows:
+x86_64-windows:
   extends: .build
   script:
     - $env:CHERE_INVOKING = "yes"