build: update Linux builds to run on ubuntu-latest since 20.04 is being retired

Signed-off-by: deadprogram <ron@hybridgroup.com>

.github/workflows/linux.yml

@@ -169,7 +169,7 @@ jobs:
   assert-test-linux:
     # Run all tests that can run on Linux, with LLVM assertions enabled to catch
     # potential bugs.
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -297,7 +297,7 @@ jobs:
           - goarch: arm
             toolchain: arm-linux-gnueabihf
             libc: armhf
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     needs: build-linux
     steps:
       - name: Checkout