ci: Stop testing libclang 3.9

Author: kulp

.github/workflows/bindgen.yml

@@ -99,7 +99,7 @@ jobs:
           - debian: null
             cross: null
             rust: null
-        llvm_version: ["3.9", "4.0", "5.0", "9.0"]
+        llvm_version: ["4.0", "5.0", "9.0"]
         main_tests: [1]
         release_build: [0, 1]
         no_default_features: [0, 1]
@@ -110,13 +110,8 @@ jobs:
         feature_testing_only_docs: [0]
 
         exclude:
-          # 3.9 and 4.0 are too old to support regular dynamic linking, so this
+          # 4.0 is too old to support regular dynamic linking, so this
           # is not expected to work.
-          - os: ubuntu-latest
-            llvm_version: "3.9"
-            no_default_features: 1
-            feature_runtime: 0
-
           - os: ubuntu-latest
             llvm_version: "4.0"
             no_default_features: 1

appveyor.yml

@@ -2,9 +2,6 @@ environment:
   RUST_BACKTRACE: 1
   RUST_CHANNEL: "%Configuration%"
   matrix:
-  - TARGET: gnu
-    LLVM_VERSION: 3.9.0-2
-    BINDGEN_FEATURES: testing_only_libclang_3_9
   - TARGET: gnu
     LLVM_VERSION: 4.0.0-1
     BINDGEN_FEATURES: testing_only_libclang_4
@@ -14,9 +11,6 @@ environment:
   - TARGET: gnu
     LLVM_VERSION: 9.0.0-1
     BINDGEN_FEATURES: testing_only_libclang_9
-  - TARGET: msvc
-    LLVM_VERSION: 3.9.0
-    BINDGEN_FEATURES: testing_only_libclang_3_9
   - TARGET: msvc
     LLVM_VERSION: 4.0.0
     BINDGEN_FEATURES: testing_only_libclang_4