fix(docs): correct links in README

This PR was generated using Autosynth. 🌈

Commits in this repo since last synth:
0368864 docs(samples): update ID token samples to match others (#891)


<details><summary>Log from Synthtool</summary>

```
synthtool > Executing /tmpfs/src/git/autosynth/working_repo/synth.py.
On branch autosynth
nothing to commit, working tree clean
HEAD detached at FETCH_HEAD
nothing to commit, working tree clean
.eslintignore
.eslintrc.yml
.github/ISSUE_TEMPLATE/bug_report.md
.github/ISSUE_TEMPLATE/feature_request.md
.github/ISSUE_TEMPLATE/support_request.md
.github/PULL_REQUEST_TEMPLATE.md
.github/release-please.yml
.github/workflows/ci.yaml
.jsdoc.js
.kokoro/common.cfg
.kokoro/continuous/node10/common.cfg
.kokoro/continuous/node10/docs.cfg
.kokoro/continuous/node10/lint.cfg
.kokoro/continuous/node10/samples-test.cfg
.kokoro/continuous/node10/system-test.cfg
.kokoro/continuous/node10/test.cfg
.kokoro/continuous/node12/common.cfg
.kokoro/continuous/node12/test.cfg
.kokoro/continuous/node8/common.cfg
.kokoro/continuous/node8/test.cfg
.kokoro/docs.sh
.kokoro/lint.sh
.kokoro/presubmit/node10/common.cfg
.kokoro/presubmit/node10/docs.cfg
.kokoro/presubmit/node10/lint.cfg
.kokoro/presubmit/node10/samples-test.cfg
.kokoro/presubmit/node10/system-test.cfg
.kokoro/presubmit/node10/test.cfg
.kokoro/presubmit/node12/common.cfg
.kokoro/presubmit/node12/test.cfg
.kokoro/presubmit/node8/common.cfg
.kokoro/presubmit/node8/test.cfg
.kokoro/presubmit/windows/common.cfg
.kokoro/presubmit/windows/test.cfg
.kokoro/publish.sh
.kokoro/release/docs.cfg
.kokoro/release/docs.sh
.kokoro/release/publish.cfg
.kokoro/samples-test.sh
.kokoro/system-test.sh
.kokoro/test.bat
.kokoro/test.sh
.kokoro/trampoline.sh
.nycrc
.prettierignore
.prettierrc
CODE_OF_CONDUCT.md
CONTRIBUTING.md
LICENSE
README.md
codecov.yaml
renovate.json
samples/README.md
synthtool > Wrote metadata to synth.metadata.

```
</details>

samples/README.md

@@ -23,7 +23,7 @@
   * [Keyfile](#keyfile)
   * [Oauth2-code Verifier](#oauth2-code-verifier)
   * [Oauth2](#oauth2)
-  * [Verify Id Token-iap](#verify-id-token-iap)
+  * [Verifying ID Tokens from Identity-Aware Proxy (IAP)](#verifying-id-tokens-from-identity-aware-proxy-iap)
   * [Verify Id Token](#verify-id-token)
 
 ## Before you begin
@@ -232,7 +232,9 @@ __Usage:__
 
 
 
-### Verify Id Token-iap
+### Verifying ID Tokens from Identity-Aware Proxy (IAP)
+
+Verifying the signed token from the header of an IAP-protected resource.
 
 View the [source code](https://github.com/googleapis/google-auth-library-nodejs/blob/master/samples/verifyIdToken-iap.js).
 
@@ -241,7 +243,7 @@ View the [source code](https://github.com/googleapis/google-auth-library-nodejs/
 __Usage:__
 
 
-`node samples/verifyIdToken-iap.js`
+`node verifyIdToken-iap.js <iap-jwt> [<project-number>] [<project-id>] [<backend-service-id>]`
 
 
 -----

synth.metadata

@@ -1,11 +1,11 @@
 {
-  "updateTime": "2020-02-14T12:07:57.919077Z",
+  "updateTime": "2020-02-18T18:56:56.357325Z",
   "sources": [
     {
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/google-auth-library-nodejs.git",
-        "sha": "c532b1471becf998743c803c992ab1ec9e29862c"
+        "sha": "0368864e309b70df919011235bc9b14bd8367e6e"
       }
     },
     {