chore: bump rust toolchain

[hanabi1224]

Summary of changes

Changes introduced in this pull request:

• upgrade rust toolchain to 1.79.0
• fix clippy warnings

warning: field `0` is never read
  --> src/libp2p/rpc/mod.rs:56:8
   |
56 |     Io(io::Error),
   |     -- ^^^^^^^^^
   |     |
   |     field in this variant
   |
   = note: `#[warn(dead_code)]` on by default
help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
   |
56 |     Io(()),
   |        ~~

warning: fields `source` and `request` are never read
  --> src/libp2p/service.rs:94:9
   |
93 |     HelloRequestInbound {
   |     ------------------- fields in this variant
94 |         source: PeerId,
   |         ^^^^^^
95 |         request: HelloRequest,
   |         ^^^^^^^

warning: field `request_id` is never read
   --> src/libp2p/service.rs:102:9
    |
101 |     HelloRequestOutbound {
    |     -------------------- field in this variant
102 |         request_id: request_response::OutboundRequestId,
    |         ^^^^^^^^^^

warning: field `request_id` is never read
   --> src/libp2p/service.rs:105:9
    |
104 |     HelloResponseInbound {
    |     -------------------- field in this variant
105 |         request_id: request_response::OutboundRequestId,
    |         ^^^^^^^^^^

warning: field `request_id` is never read
   --> src/libp2p/service.rs:108:9
    |
107 |     ChainExchangeRequestOutbound {
    |     ---------------------------- field in this variant
108 |         request_id: request_response::OutboundRequestId,
    |         ^^^^^^^^^^

warning: field `request_id` is never read
   --> src/libp2p/service.rs:111:9
    |
110 |     ChainExchangeResponseInbound {
    |     ---------------------------- field in this variant
111 |         request_id: request_response::OutboundRequestId,
    |         ^^^^^^^^^^

warning: field `request_id` is never read
   --> src/libp2p/service.rs:114:9
    |
113 |     ChainExchangeRequestInbound {
    |     --------------------------- field in this variant
114 |         request_id: request_response::InboundRequestId,
    |         ^^^^^^^^^^

warning: field `request_id` is never read
   --> src/libp2p/service.rs:117:9
    |
116 |     ChainExchangeResponseOutbound {
    |     ----------------------------- field in this variant
117 |         request_id: request_response::InboundRequestId,
    |         ^^^^^^^^^^

warning: field `min_gas_price` is never read
   --> src/message_pool/msgpool/msg_pool.rs:181:9
    |
170 | pub struct MessagePool<T> {
    |            ----------- field in this struct
...
181 |     pub min_gas_price: BigInt,
    |         ^^^^^^^^^^^^^

warning: usage of a legacy numeric constant
  --> src/libp2p/discovery.rs:83:32
   |
83 |             target_peer_count: std::u64::MAX,
   |                                ^^^^^^^^^^^^^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
   = note: `#[warn(clippy::legacy_numeric_constants)]` on by default
help: use the associated constant instead
   |
83 |             target_peer_count: u64::MAX,
   |                                ~~~~~~~~

warning: usage of a legacy numeric constant
   --> src/message_pool/msg_chain.rs:569:30
    |
569 |     if (a - b).abs() <= (a * std::f64::EPSILON).abs() {
    |                              ^^^^^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
help: use the associated constant instead
    |
569 |     if (a - b).abs() <= (a * f64::EPSILON).abs() {
    |                              ~~~~~~~~~~~~

warning: `forest-filecoin` (lib) generated 11 warnings
warning: `forest-filecoin` (lib test) generated 11 warnings (11 duplicates)

Reference issue to close (if applicable)

Closes

Other information and links

https://releases.rs/docs/1.79.0/

Change checklist

• [x] I have performed a self-review of my own code,
• [x] I have made corresponding changes to the documentation,
• [x] I have added tests that prove my fix is effective or that my feature works (if possible),
• [x] I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.