Add Kubernetes 1.29.x in test matrix

[norbjd]

Fixes #22.

Also fixes a flaky e2e test (when pod takes < 1 second to start, test will try to divide by zero: https://github.com/norbjd/k8s-pod-cpu-booster/actions/runs/8316283069/job/22755561778#step:8:44). So we will add 1 to avoid it. Adding a second won't really affect the result.

[INFO] pod-with-default-boost pod took 0 second(s) to be ready
[INFO] pod-no-boost pod took 7 second(s) to be ready
[INFO] pod from deployment-with-default-boost deployment took 0 second(s) to be ready
[INFO] pod from deployment-no-boost deployment took 7 second(s) to be ready
./test/e2e-kind.sh: line 46: 7 / 0 : division by 0 (error token is "0 ")
./test/e2e-kind.sh: line 48: 7 / 0 : division by 0 (error token is "0 ")

This is a temporary fix until #17 is solved.