chore(gh): Automatically update cargo-credential MSRV

.github/renovate.json5

@@ -22,6 +22,19 @@
       packageNameTemplate: 'rust-lang/rust',
       datasourceTemplate: 'github-releases',
     },
+    {
+      customType: 'regex',
+      fileMatch: [
+        'Cargo.toml$',
+      ],
+      matchStrings: [
+        '\bMSRV:3\b.*?(?<currentValue>\\d+\\.\\d+(\\.\\d+)?)',
+        '(?<currentValue>\\d+\\.\\d+(\\.\\d+)?).*?\bMSRV:3\b',
+      ],
+      depNameTemplate: 'MSRV:3',  // Support 3 versions of rustc
+      packageNameTemplate: 'rust-lang/rust',
+      datasourceTemplate: 'github-releases',
+    },
   ],
   packageRules: [
     {
@@ -32,10 +45,26 @@
       matchPackageNames: [
         'MSRV:1',
       ],
+      schedule: [
+        '* * * * *',
+      ],
+      groupName: 'msrv',
+    },
+    {
+      commitMessageTopic: 'MSRV (3 versions)',
+      matchManagers: [
+        'regex',
+      ],
+      matchPackageNames: [
+        'MSRV:3',
+      ],
       "extractVersion": "^(?<version>\\d+\\.\\d+)",  // Drop the patch version
       schedule: [
         '* * * * *',
       ],
+      minimumReleaseAge: '85 days',  // 2 releases back * 6 weeks per release * 7 days per week + 1
+      internalChecksFilter: 'strict',
+      groupName: 'msrv',
     },
     // Goals:
     // - Rollup safe upgrades to reduce CI runner load

credential/cargo-credential/Cargo.toml

@@ -3,7 +3,7 @@ name = "cargo-credential"
 version = "0.4.0"
 edition.workspace = true
 license.workspace = true
-rust-version = "1.70.0"
+rust-version = "1.70.0"  # MSRV:3
 repository = "https://github.com/rust-lang/cargo"
 description = "A library to assist writing Cargo credential helpers."