ci: Set continue-on-error for matrix jobs

Reasoning is we want to extract as much signal as possible in one-shot.
Sometimes PRs can enter a whack-a-mole state where you iteratively fix
one job at a time. This is time consuming and frustrating.

Better to run all the jobs to completion (trade off compute resources
for human time).

.github/workflows/ci.yml

@@ -29,6 +29,7 @@ jobs:
 
   build_test:
     runs-on: ubuntu-latest
+    continue-on-error: true
     strategy:
       matrix:
         env:

.github/workflows/distros.yml

@@ -10,6 +10,7 @@ concurrency:
 jobs:
   build:
     runs-on: ubuntu-latest
+    continue-on-error: true
     strategy:
       matrix:
         dockerfile: