Fix typos in USAGE.md (#288)

Fixes #287

Author: jaxxstar

USAGE.md

@@ -422,8 +422,8 @@ Get-GitHubRepositoryContributor -OwnerName 'PowerShell' -RepositoryName 'PowerSh
 #### Querying Team and Organization Membership
 
 ```powershell
-$organizationMembers = Get-GitHubOrganizationMembers -OrganizationName 'OrganizationName'
-$teamMembers = Get-GitHubTeamMembers -OrganizationName 'OrganizationName' -TeamName 'TeamName'
+$organizationMembers = Get-GitHubOrganizationMember -OrganizationName 'OrganizationName'
+$teamMembers = Get-GitHubTeamMember -OrganizationName 'OrganizationName' -TeamName 'TeamName'
 ```
 
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