Linter: Update toolchain

[jubnzv]

Summary

• [n] y/n | Does it introduce breaking changes?
• [n] y/n | Is it dependant on the specific version of cargo-contract or pallet-contracts?

Update the toolchain version and the uses of internal rustc APIs.

Description

It would be beneficial to compile both the linter and cargo-contract using the same toolchain version. This approach would prevent the need to build a second toolchain in the CI and on user's machine when compiling a contract.

The necessity of this update because subxt, a dependency of cargo-contract, requires rustc version 1.74.0 or higher, therefore cargo-contract cannot be built with the toolchain used in the linter before this PR.

Checklist before requesting a review

• [x] My code follows the style guidelines of this project
• [ ] I have added an entry to CHANGELOG.md
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] Any dependent changes have been merged and published in downstream modules

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (b05e7f2) 53.60% compared to head (c2847fc) 53.60%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2067 +/- ## ======================================= Coverage 53.60% 53.60% ======================================= Files 224 224 Lines 7107 7107 Branches 3146 3146 ======================================= Hits 3810 3810 Misses 3297 3297 ```

:umbrella: View full report in Codecov by Sentry.
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[github-actions[bot]]

🦑 📈 ink! Example Contracts ‒ Changes Report 📉 🦑

These are the results when building the integration-tests/* contracts from this branch with cargo-contract and comparing them to ink! master:

Contract	Upstream Size (kB)	PR Size (kB)	Diff (kB)	Diff (%)	Change
basic-contract-caller	3.207	3.207	0	0	:heavy_minus_sign:
basic-contract-caller/other-contract	1.581	1.581	0	0	:heavy_minus_sign:
call-builder-return-value	8.904	8.904	0	0	:heavy_minus_sign:
call-runtime	2.013	2.013	0	0	:heavy_minus_sign:
conditional-compilation	1.453	1.453	0	0	:heavy_minus_sign:
contract-storage	7.336	7.336	0	0	:heavy_minus_sign:
contract-terminate	1.336	1.336	0	0	:heavy_minus_sign:
contract-transfer	1.693	1.693	0	0	:heavy_minus_sign:
custom-allocator	7.652	7.652	0	0	:heavy_minus_sign:
dns	7.321	7.321	0	0	:heavy_minus_sign:
e2e-call-runtime	1.302	1.302	0	0	:heavy_minus_sign:
e2e-runtime-only-backend	1.879	1.879	0	0	:heavy_minus_sign:
erc1155	14.123	14.123	0	0	:heavy_minus_sign:
erc20	6.918	6.918	0	0	:heavy_minus_sign:
erc721	9.816	9.816	0	0	:heavy_minus_sign:
events	5.264	5.264	0	0	:heavy_minus_sign:
flipper	1.637	1.637	0	0	:heavy_minus_sign:
incrementer	1.504	1.504	0	0	:heavy_minus_sign:
lang-err-integration-tests/call-builder-delegate	2.561	2.561	0	0	:heavy_minus_sign:
lang-err-integration-tests/call-builder	5.087	5.087	0	0	:heavy_minus_sign:
lang-err-integration-tests/constructors-return-value	1.987	1.987	0	0	:heavy_minus_sign:
lang-err-integration-tests/contract-ref	4.568	4.568	0	0	:heavy_minus_sign:
lang-err-integration-tests/integration-flipper	1.815	1.815	0	0	:heavy_minus_sign:
lazyvec-integration-test	4.553	4.553	0	0	:heavy_minus_sign:
mapping-integration-tests	7.919	7.919	0	0	:heavy_minus_sign:
mother	12.756	12.756	0	0	:heavy_minus_sign:
multi-contract-caller	6.155	6.155	0	0	:heavy_minus_sign:
multi-contract-caller/accumulator	1.378	1.378	0	0	:heavy_minus_sign:
multi-contract-caller/adder	1.908	1.908	0	0	:heavy_minus_sign:
multi-contract-caller/subber	1.928	1.928	0	0	:heavy_minus_sign:
multisig	21.621	21.621	0	0	:heavy_minus_sign:
payment-channel	5.653	5.653	0	0	:heavy_minus_sign:
sr25519-verification	1.148	1.148	0	0	:heavy_minus_sign:
static-buffer	1.649	1.649	0	0	:heavy_minus_sign:
trait-dyn-cross-contract-calls	2.706	2.706	0	0	:heavy_minus_sign:
trait-dyn-cross-contract-calls/contracts/incrementer	1.549	1.549	0	0	:heavy_minus_sign:
trait-erc20	7.294	7.294	0	0	:heavy_minus_sign:
trait-flipper	1.453	1.453	0	0	:heavy_minus_sign:
trait-incrementer	1.614	1.614	0	0	:heavy_minus_sign:
upgradeable-contracts/delegator	3.152	3.152	0	0	:heavy_minus_sign:
upgradeable-contracts/delegator/delegatee	1.613	1.613	0	0	:heavy_minus_sign:
upgradeable-contracts/set-code-hash	1.747	1.747	0	0	:heavy_minus_sign:
upgradeable-contracts/set-code-hash/updated-incrementer	1.726	1.726	0	0	:heavy_minus_sign:
wildcard-selector	2.852	2.852	0	0	:heavy_minus_sign:

Link to the run | Last update: Fri Jan 19 15:00:54 CET 2024