ci: bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v3...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build_examples_platformio.yaml

@@ -41,7 +41,7 @@ jobs:
           ]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Set variables
         run: |

src/TinyGsmModem.tpp

@@ -203,7 +203,6 @@ class TinyGsmModem {
       if (check_signal) { thisModem().getSignalQuality(); }
       if (thisModem().isNetworkConnected()) { return true; }
       delay(250);
-      esp_task_wdt_reset();
     }
     return false;
   }