workflows: Discard mainline and RT build artifacts after 5 and 30 days

To reduce the size of the stored Github artifacts, retain the mainline
builds (arm/bcm2835_defconfig and arm64/arm64) for 5 days, and the
bcm2711_rt build for 30. The main ones are retained for 90 days.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

Author: 6by9

.github/workflows/kernel-build.yml

@@ -24,36 +24,43 @@ jobs:
             arch: arm
             defconfig: bcm2835_defconfig
             kernel: kernel
+            retention: 5
 
           - name: arm64
             arch: arm64
             defconfig: defconfig
             kernel: kernel8
+            retention: 5
 
           - name: bcmrpi
             arch: arm
             defconfig: bcmrpi_defconfig
             kernel: kernel
+            retention: 90
 
           - name: bcm2709
             arch: arm
             defconfig: bcm2709_defconfig
             kernel: kernel7
+            retention: 90
 
           - name: bcm2711
             arch: arm64
             defconfig: bcm2711_defconfig
             kernel: kernel8
+            retention: 90
 
           - name: bcm2711_rt
             arch: arm64
             defconfig: bcm2711_rt_defconfig
             kernel: kernel8_rt
+            retention: 30
 
           - name: bcm2712
             arch: arm64
             defconfig: bcm2712_defconfig
             kernel: kernel_2712
+            retention: 90
 
     steps:
     - name: Install armhf crossbuild toolchain
@@ -100,4 +107,4 @@ jobs:
       with:
         name: ${{matrix.name}}_build
         path: ${{matrix.name}}_build.tar
-        retention-days: 90
+        retention-days: ${{matrix.retention}}