ci: build test fails randomly

[tmigone]

Build test fails randomly when ran on GitHub actions:

[@graphprotocol/contracts]: An unexpected error occurred:
[@graphprotocol/contracts]: 
[@graphprotocol/contracts]: Error: spawn /home/runner/.cache/hardhat-nodejs/compilers-v2/linux-amd64/solc-linux-amd64-v0.7.6+commit.7338295f EACCES
[@graphprotocol/contracts]:     at Process.ChildProcess._handle.onexit (node:internal/child_process:284:19)
[@graphprotocol/contracts]:     at onErrorNT (node:internal/child_process:477:16)
[@graphprotocol/contracts]:     at processTicksAndRejections (node:internal/process/task_queues:82:21) {
[@graphprotocol/contracts]:   errno: -13,
[@graphprotocol/contracts]:   code: 'EACCES',
[@graphprotocol/contracts]:   syscall: 'spawn /home/runner/.cache/hardhat-nodejs/compilers-v2/linux-amd64/solc-linux-amd64-v0.7.6+commit.7338295f',
[@graphprotocol/contracts]:   path: '/home/runner/.cache/hardhat-nodejs/compilers-v2/linux-amd64/solc-linux-amd64-v0.7.6+commit.7338295f',
[@graphprotocol/contracts]:   spawnargs: [ '--standard-json' ],
[@graphprotocol/contracts]:   cmd: '/home/runner/.cache/hardhat-nodejs/compilers-v2/linux-amd64/solc-linux-amd64-v0.7.6+commit.7338295f --standard-json'
[@graphprotocol/contracts]: }
[@graphprotocol/contracts]: Process exited (exit code 1), completed in 8s 876ms

[@graphprotocol/sdk]: Process started
[@graphprotocol/sdk]: 
[@graphprotocol/sdk]: > @graphprotocol/[email protected] clean
[@graphprotocol/sdk]: > rm -rf build
[@graphprotocol/sdk]: 
Error: [@graphprotocol/sdk]: src/deployments/network/actions/bridge-to-l1.ts(10,56): error TS2306: File '/home/runner/work/contracts/contracts/packages/contracts/index.d.ts' is not a module.
Error: [@graphprotocol/sdk]: src/deployments/network/actions/bridge-to-l1.ts(141,54): error TS2345: Argument of type 'string | undefined' is not assignable to parameter of type 'string | TransactionReceipt'.
[@graphprotocol/sdk]:   Type 'undefined' is not assignable to type 'string | TransactionReceipt'.
Error: [@graphprotocol/sdk]: src/deployments/network/deployment/contracts/load.ts(44,8): error TS2306: File '/home/runner/work/contracts/contracts/packages/contracts/index.d.ts' is not a module.
Error: [@graphprotocol/sdk]: src/helpers/epoch.ts(2,35): error TS2306: File '/home/runner/work/contracts/contracts/packages/contracts/index.d.ts' is not a module.
[@graphprotocol/sdk]: Process exited (exit code 1), completed in 2s 756ms
Done in 11s 639ms
Error: Process completed with exit code 1.

This is a known problem with hardhat:

• https://github.com/NomicFoundation/hardhat/issues/4490 (if this is the root cause, updating to latest hardhat could solve it)
• https://github.com/NomicFoundation/hardhat/issues/4491 (this is most likely the root cause)