Bump NPD version to v0.8.20-71-gf6bb4f7b-gke.0

https://gke-internal.googlesource.com/kubernetes/node-problem-detector/+log/f6bb4f7b5506e8bc9cb8b8e2b1c7ef009fa628c0

This NPD version contains the following 2 changes needed:
- High CVE fix: kubernetes/node-problem-detector#1035
- Custom metrics fix: kubernetes/node-problem-detector#1024

This NPD version is promoted at https://critique.corp.google.com/cl/736379160

```
$ gsutil cp "gs://gke-release-staging/node-problem-detector/node-problem-detector-v0.8.20-71-gf6bb4f7b-gke.0*tar.gz.sha512" .
$ cat *
254af832178eafa4666722b507a2556f331798c84fe9dcb9105c518d0842c13fc6f9f1fb297fe5ffa1f4656a6bfe1b6cd396175d9e2c748e3e9c6d092706bfaa  node-problem-detector-v0.8.20-71-gf6bb4f7b-gke.0-linux_amd64.tar.gz
0e2680ad176aa745c4f68f3bdf6bdd59c3d193c6605cbeb4b0192e4bc34c2d9240f6738090111d8bbfc2d7a016ee9854f02c8eaa8c7cb1543a8fe5951be0bd7a  node-problem-detector-v0.8.20-71-gf6bb4f7b-gke.0-linux_arm64.tar.gz
81e89cf9f7af0be608d9b432afb9b76ab11792d143b8529d2600bd3d9276c3b78c9548fd179f43b9626f38c115b6b0fa906f2927d72314457b4faca68b1c636e  node-problem-detector-v0.8.20-71-gf6bb4f7b-gke.0-windows_amd64.tar.gz
```

BUG: 384629347
BUG: 394504964

Change-Id: Ied5cb95672bf906c339561282899d24bf311a645

Author: wangzhen127

gke/cluster/gce/gci/configure.sh

@@ -29,9 +29,9 @@ DEFAULT_CNI_VERSION='v1.5.0-gke.3'
 DEFAULT_CNI_HASH_LINUX_AMD64='b53474f2a4109e9c54a4f526386a6311622e96b739109abdd77d7f063220c8be04f2b36e23f5c8eba37dc664b833b3a920acbfe04e170667835f30ccdbba0bbf'
 DEFAULT_CNI_HASH_LINUX_ARM64='32c0093c87fe46a4243d382b16184d98cd14411dfb590552baaad10d2ba115682c77e39ed60fffb9e06ed3e9ea666ee6618fd7ecbc81ba9f3b49e700991e5d38'
 
-DEFAULT_NPD_VERSION='v0.8.20-0-g53e0152f-gke.0'
-DEFAULT_NPD_HASH_AMD64='f3d29f8d5ff0ada78cabe5ab0fe40d1edcd9b57c549e8579013942841ea6f99fb7e8009ab859a817704066711282e91993820494bfce11b3b0e1415a956d96f2'
-DEFAULT_NPD_HASH_ARM64='5c1df7dca0989e8f89f3c99ca0b770779a16fd54451fb4d28d30b69bb1113e66cdd92d089f5600e8bd5941e33b2a52d5fd14e21d1cd0be804318f5a425926d36'
+DEFAULT_NPD_VERSION='v0.8.20-71-gf6bb4f7b-gke.0'
+DEFAULT_NPD_HASH_AMD64='254af832178eafa4666722b507a2556f331798c84fe9dcb9105c518d0842c13fc6f9f1fb297fe5ffa1f4656a6bfe1b6cd396175d9e2c748e3e9c6d092706bfaa'
+DEFAULT_NPD_HASH_ARM64='0e2680ad176aa745c4f68f3bdf6bdd59c3d193c6605cbeb4b0192e4bc34c2d9240f6738090111d8bbfc2d7a016ee9854f02c8eaa8c7cb1543a8fe5951be0bd7a'
 
 NPD_CUSTOM_PLUGINS_VERSION="v1.0.23"
 NPD_CUSTOM_PLUGINS_TAR_AMD64_HASH="0513dd7c1b89dbbb20a0a214bb77dc35e5a40d7fd57172ec2e937f586b4e815abbfe260f66eec4776f68860faaa927d48755659dfb5195d806fe532272b1cbd5"