Travis CI: fix matrix and jobs sections clash

merge "matrix" and "jobs" sections under the "jobs" name
(the error identified by Travis config validation)

.travis.yml

@@ -7,19 +7,9 @@ julia:
   - 1.0
   - 1
   - nightly
-matrix:
+jobs:
   allow_failures:
     - julia: nightly
-notifications:
-  email: false
-# uncomment the following lines to override the default test script
-#script:
-#  - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi
-#  - julia -e 'using Pkg; Pkg.add(pwd()); Pkg.build("Clustering"); Pkg.test("Clustering"; coverage=true)'
-after_success:
-  - julia -e 'using Pkg, Clustering; cd(joinpath(dirname(pathof(Clustering)), "..")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())';
-
-jobs:
   include:
     - stage: "Documentation"
       julia: 1
@@ -28,3 +18,11 @@ jobs:
         - julia --project=doc/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate();'
         - julia --project=doc/ doc/make.jl
       after_success: skip
+notifications:
+  email: false
+# uncomment the following lines to override the default test script
+#script:
+#  - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi
+#  - julia -e 'using Pkg; Pkg.add(pwd()); Pkg.build("Clustering"); Pkg.test("Clustering"; coverage=true)'
+after_success:
+  - julia -e 'using Pkg, Clustering; cd(joinpath(dirname(pathof(Clustering)), "..")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())';