Remove revision from SPV_ENV_*.

Shaderc response to https://github.com/KhronosGroup/SPIRV-Tools/pull/178.
diff --git a/glslc/src/main.cc b/glslc/src/main.cc
index af073a6..38a85b2 100644
--- a/glslc/src/main.cc
+++ b/glslc/src/main.cc
@@ -119,8 +119,7 @@
       return 0;
     } else if (arg == "--version") {
       std::cout << kBuildVersion << std::endl;
-      std::cout << "Target: "
-                << spvTargetEnvDescription(SPV_ENV_UNIVERSAL_1_0_4)
+      std::cout << "Target: " << spvTargetEnvDescription(SPV_ENV_UNIVERSAL_1_0)
                 << std::endl;
       return 0;
     } else if (arg.starts_with("-o")) {
diff --git a/glslc/test/option_dashdash_version.py b/glslc/test/option_dashdash_version.py
index c275f47..65ba0bd 100644
--- a/glslc/test/option_dashdash_version.py
+++ b/glslc/test/option_dashdash_version.py
@@ -41,4 +41,4 @@
 class TestVersionContainsTarget(expect.StdoutMatch, expect.ReturnCodeIsZero):
     """Tests --version output contains 'Target:'."""
     glslc_args = ['--version']
-    expected_stdout = re.compile('\nTarget: SPIR-V \d+\.\d+ rev \d+')
+    expected_stdout = re.compile('\nTarget: SPIR-V \d+\.\d+')