[FEAT]: support locking branches

[jefflill]

Describe the need

Octokit.net v6.0.0 does not currently support the lock_branch option when protecting branches. This is supported by the GitHub REST API.

I've forked Octokit.net repo and tweaked these files by adding LockBranch properties and will be submitting a pull request in a few minutes. This was a fairly simple change that should be backwards compatible for most people. The only compatibility issue is the BranchProtectionSettings constructor with the parameters. I added a lockBranch parameter which will break old code, but this seems desirable and was required by the unit tests:

    public class BranchProtectionSettings
    {
        public BranchProtectionSettings() { }

        public BranchProtectionSettings(BranchProtectionRequiredStatusChecks requiredStatusChecks,
                                        BranchProtectionRequiredReviews requiredPullRequestReviews,
                                        BranchProtectionPushRestrictions restrictions,
                                        EnforceAdmins enforceAdmins,
                                        EnforceLock lockBranch,
                                        BranchProtectionEnabledCommon requiredLinearHistory,
                                        BranchProtectionEnabledCommon allowForcePushes,
                                        BranchProtectionEnabledCommon allowDeletions,
                                        BranchProtectionEnabledCommon blockCreations,
                                        BranchProtectionEnabledCommon requiredConversationResolution,
                                        BranchProtectionEnabledCommon requiredSignatures)
        {
            RequiredStatusChecks = requiredStatusChecks;
            RequiredPullRequestReviews = requiredPullRequestReviews;
            Restrictions = restrictions;
            EnforceAdmins = enforceAdmins;
            LockBranch = lockBranch;
            RequiredLinearHistory = requiredLinearHistory;
            AllowForcePushes = allowForcePushes;
            AllowDeletions = allowDeletions;
            BlockCreations = blockCreations;
            RequiredConversationResolution = requiredConversationResolution;
            RequiredSignatures = requiredSignatures;
        }

I've built a temporary nuget including this functionality: https://www.nuget.org/packages/Neon.Octokit/6.0.1

SDK Version

No response

API Version

No response

Relevant log output

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Code of Conduct

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