Modernize the Documenter setup

.travis.yml

@@ -13,4 +13,12 @@ notifications:
 #  - julia -e 'Pkg.clone(pwd()); Pkg.build("Survival"); Pkg.test("Survival"; coverage=true)';
 after_success:
   - julia -e 'using Pkg; Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())';
-  - julia -e 'using Pkg; Pkg.add("Documenter"); include(joinpath("docs", "make.jl"))';
+jobs:
+  include:
+    - stage: "Documentation"
+      julia: 1.0
+      os: linux
+      script:
+        - julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
+        - julia --project=docs/ docs/make.jl
+      after_success: skip

docs/Project.toml

@@ -0,0 +1,6 @@
+[deps]
+Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
+Survival = "8a913413-2070-5976-9d4c-2b364fdc2f7f"
+
+[compat]
+Documenter = "~0.20"

docs/make.jl

@@ -2,8 +2,6 @@ using Survival, Documenter
 
 makedocs(
     modules = [Survival],
-    clean = false,
-    format = :html,
     sitename = "Survival.jl",
     authors = "Alex Arslan",
     pages = [
@@ -18,6 +16,4 @@ makedocs(
 deploydocs(
     repo = "github.com/ararslan/Survival.jl.git",
     target = "build",
-    deps = nothing,
-    make = nothing,
 )