Add ArbOS 40 Callisto network upgrade dates (#1000)

Author: leeederek

docs/network-upgrades.md

@@ -18,7 +18,8 @@ Visit [Inside Arbitrum Nitro](https://docs.arbitrum.io/inside-arbitrum-nitro/) t
 
 | Upgrade         | Governance Approval Status | Link to most recent governance stage             | Arbitrum Sepolia (YYYY-MM-DD)    | Arbitrum One (YYYY-MM-DD) | Arbitrum Nova     (YYYY-MM-DD)      |
 |-----------------|----------------------------|--------------------------------------------------|----------------------------------|---------------------------|-------------------------------------|
-| [Arbitrum BoLD](https://docs.arbitrum.io/how-arbitrum-works/bold/gentle-introduction) | Approved & executed | [On-chain Tally vote](https://www.tally.xyz/gov/arbitrum/proposal/101924107818180443784046677916233531742645798596604549673138282938475874935972?govId=eip155:42161:0xf07DeD9dC292157749B6Fd268E37DF6EA38395B9) | [Weds, 2024-12-11 06:21:36 PM UTC](https://sepolia.etherscan.io/tx/0x84950b761493e33b792986b66201401fce921cc75ad2e1811fea3f2644a27b99) | [Wed, Feb 12, 2025 02:00:11 PM UTC](https://etherscan.io/tx/0xe9788a104f8443b5900e54f8c887f0522d121487fc343a1ff90e1e6ed987967e) | [Wed, Feb 12, 2025 02:00:11 PM UTC](https://etherscan.io/tx/0xe9788a104f8443b5900e54f8c887f0522d121487fc343a1ff90e1e6ed987967e) |
+| [ArbOS 40 Callisto](https://docs.arbitrum.io/node-running/reference/arbos-software-releases/arbos40) | Pending on-chain Tally vote | [Snapshot vote](https://snapshot.box/#/s:arbitrumfoundation.eth/proposal/0x7cc26491a070c74c1a4ec5a9892571d31eb690015936a35b52c0d3a97bd5497f) | [Mon, 2025-05-06 at 02:54:45 PM UTC](https://sepolia.arbiscan.io/tx/0xce8d716391583d10e6c7b27d17118b9e2845cbb44321b466adff1b9168603a40) | Tues, 2025-06-17 4:00:00 PM UTC | Tues, 2025-06-17 4:00:00 PM UTC |
+| [Arbitrum BoLD](https://docs.arbitrum.io/how-arbitrum-works/bold/gentle-introduction) | Approved & executed | [On-chain Tally vote](https://www.tally.xyz/gov/arbitrum/proposal/101924107818180443784046677916233531742645798596604549673138282938475874935972?govId=eip155:42161:0xf07DeD9dC292157749B6Fd268E37DF6EA38395B9) | [Weds, 2024-12-11 06:21:36 PM UTC](https://sepolia.etherscan.io/tx/0x84950b761493e33b792986b66201401fce921cc75ad2e1811fea3f2644a27b99) | [Wed, 2025-02-12 02:00:11 PM UTC](https://etherscan.io/tx/0xe9788a104f8443b5900e54f8c887f0522d121487fc343a1ff90e1e6ed987967e) | [Wed, 2025-02-12 02:00:11 PM UTC](https://etherscan.io/tx/0xe9788a104f8443b5900e54f8c887f0522d121487fc343a1ff90e1e6ed987967e) |
 | [ArbOS 32 Bianca](https://docs.arbitrum.io/run-arbitrum-node/arbos-releases/arbos32)     | Approved & executed by the Arbitrum Security Council | N/A  | [Weds, 2024-09-25 at 02:06:01 UTC](https://sepolia.arbiscan.io/tx/0x180d29cc945cbedbb7076d721560cecbde71cda9b61a1614535f88e712dce692)  | [Weds, 2024-09-25 at 02:37:30 UTC](https://arbiscan.io/tx/0x28f3ae9002bd49f4bbcb6ffa48b2e8f30692f7fdf0b9d84e4c2a4e0b75d732e8) | [Weds, 2024-09-25 at 02:26:11 UTC](https://nova.arbiscan.io/tx/0x77224d12d0154bf971094202a5e24cbc21b7e8f1bef2d716098e9fc9b34202b7) |
 | ArbOS 31 Bianca | Approved & executed | [On-chain Tally vote](https://www.tally.xyz/gov/arbitrum/proposal/108288822474129076868455956066667369439381709547570289793612729242368710728616) | Mon, 2024-06-17 at 17:00:00 UTC  | Tues, 2024-09-03 at 17:00:00 UTC | Tues, 2024-09-03 at 17:00:00 UTC |
 | [ArbOS 20 Atlas](https://docs.arbitrum.io/node-running/reference/arbos-software-releases/arbos20) | Approved & executed             | [On-chain Tally vote](https://www.tally.xyz/gov/arbitrum/proposal/46905320292877192134536823079608810426433248493109520384601548724615383601450?chart=bubble)         | Thu, 2024-02-29 at 18:00:00 UTC  | Thu, 2024-03-14 01:48:09 PM UTC | Thu, 2024-03-14 01:48:09 PM UTC                                               |