Remove SwiftLint's 3.0 commit

SwiftLint's first commit to include SWXMLHash's change to avoid
conflicting with `Sequence.Element` (drmohundro/SWXMLHash@ed5f34c)
was realm/SwiftLint@7acacf6,
which came after SwiftLint dropped support for Swift 3.0.

So there exists no Swift 3.0 compatible commit that also supports
Swift 4's `-swift-version=3` compatibility mode.

Author: jpsim

projects.json

@@ -2052,10 +2052,6 @@
     "path": "SwiftLint",
     "branch": "master",
     "compatibility": [
-      {
-        "version": "3.0",
-        "commit": "d8f5a316f29077cd22f7d129e8bfaf4f4238d6f1"
-      },
       {
         "version": "3.1",
         "commit": "c34c5c164954132a87e90d2312a74826a54487ed"
@@ -2073,17 +2069,7 @@
     "actions": [
       {
         "action": "BuildSwiftPackage",
-        "configuration": "release",
-        "xfail": {
-          "compatibility": {
-            "3.0": {
-              "branch": {
-                "master": "https://bugs.swift.org/browse/SR-6617",
-                "swift-4.1-branch": "https://bugs.swift.org/browse/SR-6617"
-              }
-            }
-          }
-        }
+        "configuration": "release"
       },
       {
         "action": "TestSwiftPackage"